Just FYI,the Cadent has a straight blade alloy fork. I'm seriously not a fan of alloy forks,esp when combined with skinny high-pressure tires. I stopped commuting on my Big Buzz because riding it every day started to bother my carpel tunnel.

"MTB tires" on the SU? They're street slicks. And they probably give a good ride. MTB tires are fat knobbies used off road. I've got 3 bikes with 26x1.5" tires;they all ride good and are plenty fast. In fact,the SU has the advantage in that both skinny performance tires and fat treaded tires that fit it are readily available at local LBS's. People talk about putting fat 700cc tires on bikes,but how many local shops actually have them on hand? I can go into just about any shop in the DC area and walk out with a set of 1.5",med to high pressure,puncture resistant street slicks,and a set of 2.1" knobbies for snow/trails.