I use the Garmin 3+ for my job and it works really well..... especially when interfaced into a laptop (serial port or usb connection - 4800 Baud data transfer - will update laptop mapping program's position every 3-5 seconds or so)
The military bought me the Garmin eTrex Legend fr my personal survival gear. To be honest I haven't used it much, but if they believe that downed aircrew can survive better in bad guy land with that GPS, then take that as you will. Either it was teh cheapest that was "good enough" or they honestly thought it would make a difference in our survival. Since it was my commander and not some far away Star that never met me, I'd like to think that latter is the case. My current CC is a really good, prior-enlisted O who takes an interest in us and our jobs.
-K-