I commute a couple times a week on my Salsa Casseroll (Complete/Triple), I've never had any issues. In fact, Until I picked up my Wilier I was commuting at least 4 days a week on it. I was regularly traveling about 80 miles a week on the bike. I've even tackled a few serious climbs with it, and the rear wheel stays put, although it's a pretty flexy bike.

The shimano skewer holds the wheel tight, I think that might be the key. I've heard of other folks having slippage issues (not on Casseroll's) using other skewers.

I love my Casseroll, I could probably go more than 100 miles a day and feel comfortable on it. It soaks up bumps, and is really stable. Typically I'm carrying about 25 pounds in my rear panniers, on a Tubus Cosmo rack.