I recently purchased the
Garmin Nüvi 855 GPS. As soon as I registered it the Garmin web site said it needed a flash bios update and then I could update the maps... 3 hours later I was up and running (maps are HUGE files). It has worked flawlessly and I'm very impressed by the voice recognition. I can do just about anything without touching the unit... very handy on a busy freeway at rush hour when you decide to go somewhere other than your original destination.
Before I purchased I read all the reviews on many different sites... the 800 series had some problems but most were actually caused by the user. One problem mentioned several times was volume.. before I got mine and after reading ALL the Spec's and Features, I decided that wouldn't be a problem... It has a very cool FM transmitter so it will play over your RV stereo system, plus it has a 3.5mm audio out jack so it can easily be wired to one of the Aux inputs on my stereo. After flashing the bios the volume wasn't an issue anyway.. it was plenty loud.
Another feature I soon fell in love with was the micro SD slot and what I could put on a 2gb chip... 500 of the rockin'est "Oldies But Goodies"

...remember this thing plays through my RV stereo speakers and automatically cuts the music when the GPS needs to tell me something.
I give it a