Yeah, I'd like to make it to work on time, but it's not like I'm in a race. I mean, I don't think that most people buying commuting bike are evaluating two different size bikes going, "hey which one is faster?" That just doesn't seem like that would be realistic.

There is one thing though. MTB smooth tires are ALOT more comfy than road tires. You can get the MTB tires alot wider and fatter which makes them alot more comfrotable. Seems like commuters would be more interested in comfort than speed.