I must be semi old school.. I have the Garmin Rino 130. Have taken it to Iraq and back to Idaho. Bought it in 04 and still have it. Am sure it is old school equipment now, but still works and has 2way radio as well. Paid 350.00 for it and have gotten my money worth out of it.
GPS's are similar to the Avy beacons, in the fact that there is more than one brand the prices are as vast as the models. If you are thinking about getting a GPS unit you need to do your research. What are you wanting to be able to do with the unit and how much are you willing to spend? This is really what it comes down to. Garmin is good for being able to pull locations from other garmin units, so you can locate your riding party if you get split up. Not sure what the distance is on that feature but you can research it when you are reasearching the various GPS models.