I brought a Pn-20 used from ebay and as much as I would like to rave about it I can't. I own various Garmin and Magellan hand held units; I use them for hiking and Search and Rescue purposes. I use the units in conjunction with a compass and topo maps; I pull UTM's from maps and enter them into the units and do it often.
I can say this about the Delorme: It is built well and it fits great in your hand. It is really designed well and just looks good. The Topo software that comes with the unit is excellent, better then the Garmin software, however it is more complex then the Garmin software. I have a connection issue with the used unit I purchased thus I have not been able to use it with the unit.
However it is not as accurate as any of the Garmin units I own. It is often off by 10 or 30 meters when compared to the Garmin's. It also has this odd quirk - when I try to edit a position, it won't let me save the new coordinate, it reverts to the previous entry. Also, it is slower to acquire a fix then my other units.
Maybe the newer Pn40 or 60 is better; the design has great potential.