I don't have experience on the Dueler but I run BFG TA/ko and am a HUGE fan. I've run difficult trails w/ the BFG all terrains and never had a problem. Also run them thru deep mud. Very strong sidewalls, which is important to me because they take a beating on rocks. The only problem I've had with them is on tightly packed greasy mud like we get out here in CO. In fact it's been raining here today so I snuck out to some new building sites for a little fun (
) and went sideways sliding on this type of mud as if it were black ice. Not sure if mudders would have been different, though, b/c it wasn't loose,,,it was just,,,weird.
They are also excellent in snow and have done well for me on ice as well, relative to mud terrain tires which tend to slide easily