I use it and have been for several years. It is constantly being updated and it is easy to get updates, new serials#, etc.
The downside is that it uses USGS maps which are really outdated and black and white aerial photos (unk date). So you may not be getting the most updated information which could be critical in tricky navigation areas.
The plus is it can cache map and aerial photo info on your HD for offline use in the field.
You can open up waypoints to Google Earth pretty easily. You can also scan in your own maps.
You can try EasyGPS and see if it's worth your while. I use several GPS programs and ExpertGPS is one I constantly go back to.