Pros
Although salaries are slightly lower, the benefits are good and there's a more casual attitude in general -- although this can vary depending on the group. Hours can be flexible, working from home is not exactly encouraged but is becoming more common, etc. This may be a pro or con, depending on your taste: there lot of friendly, interesting & slightly eccentric people. The staff definitely skews heavily toward liberal, but that is fairly typical for the area. There are some supervisors it is a genuine pleasure to work for & with... On the other hand, see "Cons."
Cons
The Peter Principle. Many supervisors & managers seem to be promoted up to one level beyond their capabilities. Everything in the "pros" column is completely dependent on your area & the project. Some teams support each other and some seem to think that turf battles are more important than the actual end result. This is why, as noted in another review, it is incredibly difficult to make a lateral move into another group. The review process is rather byzantine and focused mostly on avoiding lawsuits rather than, say, noticing and rewarding good employees, or correcting bad ones.