I would only recommend a Garmin and I would only recommend Mapsource Topo.  This is the only product that I know of that they provide free updates to the software and free updates to the unit firmware.  Mapsource also interacts with Google Earth,,,, SWEET !  I have been pounding my Legend for 3+ Years on the handlebar of an ATV.
Visit   
www.PaulsWackyWorld.com  to see GPS guided ATV adventures.