I use a gps all the time, My best advice to you is save your money and get the best one you can afford. I have a Garmin Rhino 130, cost $400.00 new a while back. It has a radio, (gmrs,fmrs) and a compass that works even if you arent moving, but the best feature (for me) is the track, trackback feature, it has gotten me back to camp in the dead of night many times.
of course it has all the other features like peer to peer positioning, location marking, route building etc, etc.