OldsCOOL; This is BF...what do you expect. The only thing I see with mountain bike riding as a negative is too much hill climbing and not enough high cadence work in the drops. Let's face it. Unless one rides a mountain bike next to a river, one is going to have to climb a lot. If you climb a lot, you will get good at climbing. IMO, the power meter takes away the aspect of riding a heavy bike for training and then switching to a light bike for events such that it feels easier. If you do power climbing intervals, the weight of the bike, road conditions and wind are taken out of the equation.