Pros
There are some really amazing hackers here One of the few places to work on really low-level compiler OS code Your code is used for critical software, from missiles to pace-makers to nuclear reactors Amazing recruiting process
Cons
It's all proprietary software used mostly by the military and large companies. The technology you is a bit insular - this is not twitter. My first boss was absolutely incredible -- I enjoyed getting up and working for/with him. But then he left and was replaced with someone who was not quite as stellar. It makes a big difference motivation-wise. I got the feeling that the company was on a downhill slide as I was leaving. I'm sure it will remain stable and profitable but it seems like less of an exciting place to be than when I first joined.