Not getting lost

I am glad that someone has asked this question as I am going through the same dilemma myself as planning a solo France trip in just over a months time and still an undecided about getting a 705 or replying on maps. As I am camping I am worried about the battery life plus cost is a problem. I don't want to get lost but simnilarly like the idea of just following a map and my instincts.
Sorry totally pointless post!

The Garmin Edge 705 or 800 is exactly what you need.
I have full European road maps and UK topographical maps on my Edge 705, both fit on an 8GB memory card.
Do note that these Garmins don't come with maps on board so you have to purchase or "acquire" them yourself.

In Europe road signage is miles ahead of the UK. Signs telling you where the next town is and milestones every 50-100metres so you know which road and kilometre you're in.

My friends and I cycled Belgium with a pocket map. When we needed more specific street-level directions I used my Nokia E72 - their Maps software has free turn-by-turn GPS directions. You can download the maps onto your phone before your trip and use the GPS offline so you don't get stung by data charges.

It's probably quite cheap second-hand and has good battery life, although you could benefit from a spare battery (or for extra karma points you can get the Nokia Bike Charger kit). You can get a cradle to mount it on your handlebars off eBay.

An iPhone or similar with a Power Monkey should work fine.

Ask a Frenchman for directions if you get lost. In rural France, wandering into the village tabac in cycling kit typically gets you nods of approval from the Gitane-puffing old men. Tell them you are taking the time to cross their country by bike and you'll probably get a hearty "Chapeau!"

In my experience of cycling through France, maps are invaluable & can be bought cheaply in supermarkets. As pointed out signs are generally v good. You tend to use map every 20 miles or so just to check you are on track & going through the correct villages. Also good to have when unforseen problems occur such as road closures. Rare but does happen

I also have a GPS but it was a pain keeping it charged. I used one of those USB chargers that takes AA batterries. Stopped off at many Lidl stores (plentiful in France) to get cheap batteries. Also great place to stock up on cheap energy drinks and sweets!

Forget about using an iphone for cycle touring- drinks battery power & will prob end up getting broke.

Another tip - take a compass. Either use the compass feature on a GPS if you get one or for a few pounds you can get one off ebay that will fit to handle bars. I find its easy to loose your bearings especially in large towns so helps you check you are going roughly in the right direction. Nothing worse than the feeling of the realisation that you have just spent 5 miles cycling the wrong way:(

Don't worry about getting lost anyway - worse case scenario you'll just discover something new - have fun!

Use maps. Seriously - French road signing is far, far better than here. Even destination signing seems to be geared towards short distances (i.e. signs are always generally to the next town, not the next 'big' town 50 miles away like they are here). Furthermore, it's hard to find an unclassified road there, so with every road having a label on the map and often corresponding markers on the verge, it's very difficult to get lost.
I must have done 1500km of touring in France last year with just a 1:250k road atlas and didn't once have a problem.

+1 for a Garmin 800, that would be my choice. I use my garmin 305 a lot for navigation on the roadbike but it's a bit of a faf and needs to be planned. Will upgrade to an 800 @ some point but no need right now.

Failing that I used my iPhone + copilot France nav software which wasn't expensive to drive down to the south of France last year. A decent bike mount and either a piggyback battery/case or one of those USB battery packs that takes aaa's which you could strap to the bike could do the trick. The copilot software has it's own maps so no roaming charges, but you'd need to tweak the settings I guess to not be sent down every toll or main road

There's all sorts of options really. although something like a Garmin Edge 800 or a Bryton Rider 50 will do lots of other stuff, it's pretty handy as a simple mapping device too. The less fully-featured (in a bike sense) trekking GPS units are worth a look as well. You could also use a smartphone with software such as viewranger or google maps; you might have to be wary of connection charges though, and battery life can be an issue if you keep your phone on with the GPS connected.