I've used this on my Garmin etrex. I use it both for find our way through the back roads of the Dakotas so you can "see ahead" before you drive down 2-3 miles on a dirt road only to find it dead ends in a field or slough. Or to show wetlands size, to some extent access to.

I use it more so in Elk hunting out west to find our way in and out of mountaneous areas. Elevation shown are good. Pretty good representation of natural features, creeks, trails even. It can be a little challenging to get the right zoom ratio so you get perspective and still see enough detail. Also, I think there is a way to get updates from their website, which I haven't done. You can download them to your PC and that is in addition to what's already on the CDs.
Also, it lets you save your waypoints, tracks, etc. along with selected areas to groupings of maps you want to save upload/download pc to/from GPS. I always need to remind myself before going hunting to upload to my GPS the maps I for areas we're going to. Without some sort of topo map loaded in the back roads or back country a GPS is much less useful.