I have an original TomTom One, about five years old. Other than being a little slow to acquire a signal, it's excellent. Over long distances it can sometimes choose odd routes, so I tend to look at a map, but in towns it's a fantastic help and I have learned to trust it. I've used it in the UK mostly, of course, but also extensively in France, Switzerland, Spain and South Africa. I've had no problems with being able to see the screen (although I imagine if you have an open car it might be difficult) and the French female voice I have selected is even reasonably pleasant to listen to. I've used a Garmin, which I didn't find anywhere near as good.
FWIW
Jeremy