phone mount

Another vote for Quad lock here. I have tried other mounts. I like the way that mounting is easy, but removal requires a knack that a casual thief is unlikely to have. The Quad Lock 'phone case feels good in my pocket, the extra thickness isn't a problem. However it's not as good a 'bumper' as the case I would ordinarily protect my 'phone with. I'm afraid I lost the "condom" before I could test it in rain and I'm put off by the replacement price for the condom alone. I don't like the way the mount is designed exclusively for a modern wide stem. It's secure, but moves around on a handlebar, traditional stem, or "T-bar" accessory mount.

+ 1 for Quad Lock here to. 

Mounting  is easy and at the same time it is the only setup I've found that doesn't have an alarming tendency to dump the phone when the going gets seriously bumpy. 

To OP: I've got an original S5 QuadLock case if you're interested.  QuadLock is absolutely the best I've come across (I now use an S7 phone).  I'll chuck it up on eBay this weekend for a fiver and you can pick it up that way if you want.  You'd just need to buy a handlebar mount or out-front (I use both on different bikes).  Hope this is of use to you.

To: Jack Osbourne - I got the universal mount to stick to a Spigen case for my S7 with no problems (after four months).  Rock solid.

http://www.ebay.co.uk/itm/Roswheel-Bicycle-Bike-Pouch-Pannier-Frame-Front-Cell-Phone-Tube-Bag-/162192342871?hash=item25c36abf57:g:1w4AAOSwFe5XzWQM

I use something similar with my S2m very stable/secure mount and very flexible with the ratchet system, easy to remove as a whole from the mount

Quad lock here too.

Couldn't get the mount to stick to the armoured case for my HTC, but its now firmly attached to the back of a spare Sony.

Can anybody recommend a case brand that the mounts will stick to?

+1 for quad lock. I have the out front version for my S5 and it's epic.

I have been using Quad Lock Bike phone mount for over 3 months, still no complaints. Works perfectly with my Galaxy S5.
https://www.bestadvisor.com/bike-phone-mounts
Very sturdy. Good build quality. Easy to mount and no wiggle whatsoever, while I am riding. I bought an extra case just to use with this mount.

I have been using Quad Lock bike phone mount for over 3 months, still no complaints. Works perfectly with my Galaxy S5.
Very sturdy. Good build quality. It does get a little tricky to place phone on but it'll become easier as i use it. I love the minimal look and its very functional.