| Used a Garmin Etrex Vista for a couple of years off road. It survived massive abuse (although the screen needs a bang every now and then) and still serves me perfectly well.
Battery life can be a bit of problem if it's not wired in, and the software isn't exactly cutting edge, but overall no complaints. It was the only handheld at the time with a map on it but I think many of the newer units have far superior user interfaces.
If it's just for the bike I should go with one of the new traffic-focussed jobbies. If you're reckoning on using it travelling, city navigating, finding your way back to your hotel at 4am, etc... then consider a handheld! | 
Hybrid Mode
