I returned my Triton 2000 for the Colorado 400t, and I'm very pleased I did.
The Triton was a nice unit, but Magellan still has so many bugs to resolve before the unit is ready for market. I can confirm that REI has pulled them completely citing a recall direct from Magellan.
The NG Topo capability is great in theory, but in reality the screen was difficult to read and blurry at anything outside of the 300' perspective.
The Onix 400 from Bushnell allows downloads of topographic and sat/aerial shots directly from their site, but they are seriously lacking in the support department. The only plus for that unit right now is the XM weather and radio service....and yes, the weather service does work despite what many forums have stated.
I have heard great things about the Delorme, but the screen size was a little disappointing to me.
I am very pleased with the Colorado 400t which comes preloaded with Topo 2008, but that might not have the detail you're seeking.