So are we talking about mountain bikes ridden off road or other bikes ridden on pavement? Based on the OP, I thought we were talking about mountain bikes with fat tires. If so, the issue isn't comfort in the sense that a fat tire is going to help, the issue is a larger diameter tire is going to roll over obstacles easier. Obviously some folks have decided a 29" tire makes sense, I suppose the marketers are thinking maybe the folks who are resistant to going as big as 29" would be more likely to go to this new 27.5er thing. Silly, yes, but why do so many of you seem to be talking about this in regard to pavement riding? I agree, it's even more silly to add a new size for the pavement, but in regard to riding off road there's at least a functional difference worth noting (although I've obviously never ridden a "27.5er")-