We have two Ventana ECDM's a 26" and a coupled 29r. The both ride great but different. We have done two extended trips in Moab , the White Rim(26") and the Maze in Canyonlands(29r). We think that very few tandems have done the maze and only a few on the White Rim. You will be amazed what you can ride on a mtn tandem. We ride a fair amount of single track here in Alaska. Frequently we will have a fast single approach from behind on single track and we tell them to pass on the next opportunity but they usually ride behind us for a while just to watch as they can't believe a tandem can do it. We get way more comments on the mtn tandem then the road tandem. I think the 29r is overall a better ride but the longer wheel base is a challenge in some single track.