My only personal bike commuting experience is in the DC area, and it's pretty good overall. Lots of MUPs leading into the city. Once on city streets though, it's a mess. Some of the worst traffic in the US, and fairly dangerous for cyclists.

Just as an example, earlier this week, in a 4 block section where I'm forced to ride on streets in Georgetown, I had to yell at a cab not to run me over, and three other cars made various dangerous and illegal maneuvers that I had to take evasive action to keep from being hit. If you know DC, it's the area from Key Bridge until you are on the CCT under Key Bridge. A cyclist's nightmare during rush hour.