I used my wife's XOOM (android) I on my last trip.
The 10" was a little bit larger than I liked. I think a 7" would have been ideal. The RAM mount held up very well though.
This model tablet has the GPS built in - many of them do. I used Co-Pilot, and it worked reasonably well but there were some things that were annoying. I'll be looking for a better GPS app when I get my new smartphone in a couple weeks.
That above being said, using a tablet as GPS works great aside from some annoyances.
If you have time to kill, you should kill it
- and enjoy the hell out of it -
Because time is definitely killing you.