I think there's a general consensus that the best paper maps are those made by National Geographic. However, your ability to upload those maps to whatever GPS brand you choose is limited, if not impossible - Doug Paul can comment on this better.
I'm very familiar with Garmin, and not with Delorme. With Garmin, you can download the GPS tracks and waypoints to your PC using MapSource, and save them in an "eXchange" format (.gpx) which will then allow you to import that file into a map program such as those made by National Geographic. Having said that - Garmin's maps get better and better, but still not quite up to the quality of National Geographic, IMO.
Another factor to consider - I have a Garmin vehicle GPS, and find it rather straightforward to use MapSource to move GPS coordinates of trailheads from my 60CSx to vehicle into what Garmin calls a "custom POI file (Point of Interest). You might be able to do that with Delorme as well, but I don't know that from personal experience. This ability to create trailhead waypoints has less value in the East, where they are more easily found, than in the West, where sometimes it's more difficult to find the starting point than the hike itself.