I did a 15 mile ride last weekend. I really enjoy the benefits of the larger frame and longer reach. It was easier to breathe, easier to find a comfortable position, easier to change positions, just very nice to not feel cramped. I had a little soreness in the legs but I am thinking that has more to do with my lack of flexibility and 2000 miles of having my saddle too far forward than anything related to the bike. I felt great the next day, too. I also really like the 175mm cranks on this bike.
Is there any reason I couldn't/shouldn't try to achieve a similar riding position on a mountain bike as, say, when I'm on the hoods of this one? I gave my brother a big frame MTB a couple years ago and he's not using it and doesn't want it anymore. It has a 24" TT so would require nothing more than a stem swap, if that. I'd love to be able to use it as a utility/winter/back up bike.