I'm 285 and ride a Sirrus. As you say, the sirrus is closer to a road bike than the trek 7.2. (as many will point out, however, it's a hybrid, jack of all trades, master of none, but.....)
It's a popular commuter bike over in the commuter forum..my sirrus will become the full time commuter bike after I purchase a road bike in a year. I'm hoping to work up to a 100km ride on the Sirrus later this summer.
I did pop a spoke a couple weeks ago, I blame it on not getting the spokes retensioned after 300 km or so. Bring the bike back in for a tuneup (most shops provide it as part of the purchase), and talk them into retensioning the wheels as part of the tuneup.
As for 28mm tires, I keep them pumped to 110-120 psi, and they hold up.