I've had some issues with City Bikes in Chevy Chase, but nothing they didn't fix (for free). Generally, I give them good reviews.

I think the staff at Revolution rotates around a bit between the stores.

It's probably safe to say that some wrenches at most of the shops in the area are sloppier than others. I haven't heard anyone say they're in love with the service dept of any of them.

I haven't been to CH Bikes, but I've met a couple people that do their team rides. They seem to carry some good quality stuff. Specialized sponsors their racing team. I'm thinking I'll join next year if I get a job in the District (since I could only do occasional open/alumni stuff with my school team).