Pros
Nice facilities, great friends, generous PTO, generous 401k match - you get 7% salary from company if you put in 6%, work at home, jeans-casual attire at work. Some bad managers get fired. Company is profitable. I often get a chance to write and develop code for long stretches -- what I'm best at. I've worked for some really good managers here, including my current one. Top management makes good effort to appreciate employees.
Cons
If you get stuck with an awful manager, your life is hell. Be brave enough to speak up, or ask for a transfer. Often difficult balancing multiple projects and the many administrative tasks. Project timelines can often be ridiculously tight. Some employees/jobs disappear suddenly due to outsourcing to India or Indian firms, which doesn't exactly promote the idea of job security.