Cbeyond's corporate culture is awesome! Everyone is pretty laid back and there isn't too much drama or office politics compared to a lot of places. Everyone, including all of the executives, even the CEO, are given a cubicle and no office. We have plenty of conference/meeting rooms as a side bonus of this policy, but its nice because it emphasizes the culture of "anyone can talk to anyone"..
Cons
As far as I can tell, there aren't too many. There are one or two groups/teams that I know who can be less pleasant to work for, but they are the exception.