KCDW,
I have a Magellan 310 and for my usage, its fine. You programme in your waypoint/landmark and it will tell you your groundspeed, heading, bearing, course correction, time to go and cross track error. It will take 99 waypoinnts but can only store one route at a time. It has no moving map display or any of the other features found on more sophisticated GPS's.
You use it like a VOR, it will keep you on course and you use your map & flight guide for all other information. It encourages you to map-read, but keeps you honest.