I have never used Topo USA Ver. 3.0, so I can't tell you anything about it. My favorite map software though is Topo! produced by National Geographic. It has 5 levels of detail, from a state overview map down to the 7.5 minute topographical quads from the USGS. Through the software, the 7.5 minute topographical maps have been joined together seemlessly, so you can 'virtually' fly over a hunt unit, trace out a ridge line, or walk a creek drainage, and not run off the edge of the map. It also has a 3D shade feature that makes the flat topo map come to life and pop out with 3D relief.
I own 4 states of this software and love it. It will set you back about $100.00 per state, but IMO, well worth the $$$. The state of Idaho has 1800 7.5 minute topographical quads, Montana, 3000. At $4.00 a sheet at the BLM/Forest Service office, it wouldn't take long to pay for this software. Good luck in choosing your software.