GPS computer or smart phone

Edge touring plus - under £200 with openstmap for Europe and no contract and roaming fees when touring in Europe. Robust (been through the washing machine once!) I know how it works, all good. Phone as backup and for - gasp - calls and photos. Plus a battery pack for both <- good for up to 400km. Over that then dynamo to charge things up.

I can see why a phone alone might suit, but for Audax rides I want toughness and redundancy.

The Garmin non-bike mapping range, as mentioned by a few posters, are worth a look. Eg Etrex30 handles hrm, cadence (tho annoyingly you have to buy *their* speed/cadence sensor), doesn't really have some cyclocomputer/training features but location/hrm/cadence are in the gpx log. Takes AAs so battery life isn't an issue, and a pair can last 20+ hrs. Hence Etrexes of old and new flavours used by the Audax crowd. Dakota, Oregon, Montana (etc?) are similar in different sizes.

I've been using both my smartphone (Sony Xperia Z1C) and Garmin (Edge 1000) interchangeably over the past year or so. I prefer the Garmin, but if it was my own money (the Edge is a test unit) I wouldn't be able to justify the extra outlay.

some thoughts:

1) The Garmin is better designed for the job of being mounted. If you just want to record rides and you're not worried about routefinding/live data, there's no contest here: just use your phone. Mounting your phone on your bars gets a lot easier if the phone is waterproof, like the Z1C is. I just use a clip-on case with a bastardised Garmin mount on the back and it fits on the XL out-front mount, the same as the Edge. I've never had any problems with it, but there's always a slight niggle about the structural integrity of that solution.

2) There's not that much in it in terms of battery life. The Edge lasts 8-10 hours, generally; obviously the screen is on the whole time. If I use the Z1C out front and have Viewranger and Strava running, turning the screen on to check the route, I get about the same. If the screen's on full time (low brightness) then 6hrs is about the limit, still plenty for most rides. Whether you need the screen on full time depends on how you navigate. I'm still waiting for the perfect android app that'll allow you to make a route with alarm waypoints and then just wake the phone up and give you a warning, then show you map and instructions, at every turn. Viewranger is getting there, but it's not there yet. Anyone know one that is? On the Garmin I generally just show the route on the map and follow the line. Turn by turn directions are distracting and I've always found them to be a bit glitchy. In 317km of following the line yesterday, I only went wrong about 3 times and even then you know within 100m or so that you're going the wrong way.

3) having your phone out front on a mount (garmin, quadlock) makes taking pics along the way a lot easier. As soon as you have to put it in a case (or use something fiddly like a Finn mount) you'll likely not bother.

4) I find the Garmin's screen copes better with the full range of riding conditions. The phone's screen is better the brighter you go, but that impacts on battery life

Just for the sake of battery life argument, my Garmin 705 was left recording after an accident and died after just under 14 hours. Was an interesting upload to Strava. (Which they flagged immediately.)

Like with their running watches, the best cycling specific Garmins are the simplest ones. Once they try to do too much they screw it up. I was using my iPhone but couldn't find a durable power solution so got an Edge200 and haven't looked back. They work as they are meant to work and the breadcrumb course feature is fine (and doesn't suffer from the "disappearing course" issue that people have with the 510). It has none of the numerous issues that everyone I know has with the pricier models.

Based upon my recent experience with a Garmin Edge Touring Plus - has great battery life, good display, accurate speed, light & a nifty mount. However, user interfaces are rotten, Garmin Connect mapping rotten (no altitude gain on planned routes!). I got mine half price, so disappointment is perhaps 50% reduced as well. Beg / borrow one from a friend for a week or two & see if it really works for you.

Smart phone option - my Sony Xperia sits in the pocket, a back up just in case. Great battery life plus waterproof & shock proof. Rather wish I'd know about the mapping options for phone before buying.

Not that this debate really needs adding to, but I'd second the phone argument ... I use a middle-of-the-road Sony phone in a Finn bar mount (absolutely rock solid and £10 - http://www.thepocpac.co.uk/get-finn-the-smartphone-mount/) running Viewranger with map tiles downloaded. With the phone in airplane mode it drains about 10% battery per 30 miles. With wifi/3G off but 2G on it's slightly, but not much, more.

The only downside is that it's slightly more faff than it's worth to take the phone out of the mount to take photos etc. Apart from that, it's simple, cheap and very effective.

Sony xperia z3 compact - battery lasts ages. Mind you all I do is put it in my pocket or seat pack to find out where I've been at the end of the ride. I don't know if I'd want to risk mounting it on the bar...but certainly no problem about battery life, even without turning off mobile data.

I think whenever this question comes up its a pretty even split of phones vs. computers. Lets face it, if what you have works, then great. It all depends on your individual needs and where you see those needs going in the future. If you think you are going to get into touring and multiday rides, then neither a phone or a Garmin Edge are going to give several days of battery life!

Personally I tried using my phone and it sucks, I have a Nexus 4 and it isn't the best for battery life, plus if I broke it I'd be relegated to using an old iPhone 3s. For day to day use I have a Garmin 500, tells me what I need to know and battery lasts for ages. For longer rides I have a Garmin Dakota 20. Full colour touch screen, I downloaded the maps for free (openstreetmap) for the whole of England, also supports ant+, was even surprised to see it will calculate a route and provide turn by turn navigation if you give it a destination. When this runs out of batteries, I pop the back off and stick another couple of AA's in. If I forget to charge it up, as long as I remembered to bring spares I'm fine (on a long ride a couple of spares for the lights and GPS don't take up too much space)

I was all for saving up to buy a Garmin 810, but it is the Audax crowd that convinced me to look at the the eTrex and Dakota models purely because you can replace the batteries.

These days some smart phones have a better battery life than Garmins. I speak from experience, when my Garmin 800 ran out of juice on a 200km ride, and the phone which I was using as backup still had tonnes of juice left. Admittedly it was a Galaxy S3 with double capacity extended battery, but the newer Galaxy S5 has much longer battery life to start with, and you can get an extended battery for that too. I don't know if it affects the waterproofing though.

Several smart phones are now waterproof eg Galaxy S5, Sony Xperia Z3. These two both also support ANT+ which I'd strongly recommend over BTLE (which they also support) from the reliability point of view.

You can find ways to mount smartphones on the handlebars (eg quad lock), but they are never terribly neat. My main concern is whether they'll handle the shock and vibration long term. Perhaps I'm just nervous because years ago I killed a PDA by making a handlebar mount. It couldn't take the strain and the circuit board was damaged. (Admittedly by the GPS fitted into the CF slot in the top so maybe that's not fair!)

I use my Garmin because the interface is useable in gloves, and because I didn't find a satisfactory way to mount my non-waterproof phone where I could use it. Best I could find was a top-tube bag with phone window on top, but you had to look down too far.

IPbike was one of the best two android piece of software I found. It is extremely powerful and has many very clever features but it is not easy to use - you will need to spend time and effort configuring and understanding it. The developer warns users pretty much the same thing. It also isn't terribly pretty. It does support ANT+.

Ridewithgps also has a very very good piece of software. Not quite as powerful but has some very cool features including live tracking. I think you have to pay a subscription for some of the features though. Not sure if ANT+ supported or not.

Fix accuracy from a phone with good GPS/GLONASS performance is easily on a par with most dedicated units, which are often using quite out-of-date chipsets. AGPS on phones makes for quick aquisition these days too.

These days there are functions in the Strava app that you just can get with a Garmin (eg live segments), but they don't support ANT+ in the app yet! Grrr! (I hear they're working on it).

Happily using Smartphone with dynamo support.
Apps are better
Screen bigger
waterproof phone
quadlock for handlebar mounting
smart bluetooth for HR monitor
Ant+ is old technology and no longer needed.
Phone is MOTO G
App is RidewithGPS

Plus a waterproof case and mount for your phone if you want to actually use it while riding.

And then new ones when you upgrade your phone at the end of the contract.

If you want to use a smartphone with cadence & hr that's another £100 for the wahoo kit.

I did the iPhone thing. Pain in the backside if you want to use it for anything other than a Strava logger. I got a new Garmin 800 with HRM, Cadence and Maps off ebay for £220. Lasts for hours, does full route mapping, is on all the time and doesn't loose a signal. Has some unusual quirks and sometimes the mapping drives me mad but that's down to user error

I regularly do 6-7hr rides using Strava and Viewranger on my iphone 4S. Never less than 50% battery life left.

All you have to do is turn off wifi and mobile data/3G. Takes seconds and the phone is still fine for calls & texts if requited.

I keep mine in my pocket and only use it if I'm unsure at junctions as Viewranger works a treat for that sort of thing.

Garmin 800's are no where near £500 so not sure where the poster who put that comment got his pricing. If you want navigation then go for a Garmin. Also Garmins give a better fix than a phone. They are also cheaper to replace in a crash than a phone. Garmin can and do repair them which is getting harder with new phones. If you do mount the phone on your bike and manage to smash it, you're buggered if you use it for navigating or need to call for help.

http://www.wiggle.co.uk/garmin-edge-800-gps-performance-navigation-bundle/

If you're looking at going down the phone route, it depends which operating system you would be using.

My friend has an iPhone 5, which he uses with the Wahoo Bluetooth HRM and Speed/Cadence sensor which he mounts on his handlebars. The downside of this is 1) he can't keep his screen on the whole time due to battery restrictions, 2) the moment it starts raining, he puts it in his pocket.

I've recommended that he looks at the Wahoo RFLKT(+), but this is another spend which he's not willing to do yet. At the minute he simply asks me how far we've been/time and looks at the stats when he gets home.

It also depends on the software that you want to upload to?
Strava for iOS supports the wahoo, and I believe other brand peripherals, whereas for Anrdoid, it only supports the Zephyr HxM at the minute.

If you're looking at going down the Android route, make sure you purchase a phone which is running at least Android 4.3, as this has updates for the latest bluetooth stack, so should connect to some of the bluetooth heart rate monitors.

The android route is restricted by app support for heartrate and cadence sensors for the majority of mainstream upload sites (garmin, strava, training peaks etc).

Some of the newer android phones are starting to include ANT+ hardware (sony and Samsung to my knowledge), meaning that you can use the garmin accessories, but again the app support is limited.

I personally use a Garmin 500 with HRM and speed/cadence sensor and it works great!

I upload all of my rides to Garmin connect and Strava either via my PC, or by connecting the USB to my rooted Nexus 7.

If you don't like the thought of being tethered to a PC for uploading all of your rides, look for the newer models, as the majority can upload to Garmin Connect via the bluetooth on your phone, although not to Strava (to my knowledge).

I don't have much experience with other hardware, but it may be worth taking a look at http://www.dcrainmaker.com/, as he's got a lot of thorough reviews on the site!

To be clear: an iPhone will last over 12hrs on a ride, if you turn off WiFi and mobile data. Ditto mobile navigation like Viewranger, if you set the screen to be off and only wake it for turns.

Battery life simply is not an issue anymore, with the most basic of steps to manage it. Anyone flattening their battery after a few hours is not even remotely trying, and deserves to pay the Garmin tax.

Plus if you are going Audaxing, removable phone btys or external packs are very cheap nowadays.

For navigation in unfamiliar places, a phone is by far the most cost-effective solution. There's a reason virtually every SAR/mountain rescue organisation in the UK uses smartphones and Viewranger. It works, in the wilds, for a long time. It'll do a Sunday bimble on the North Downs