Pros
You are making the world a better place. Great work-life balance. Generous vacation. Nice stock purchase plan. Most folks are relaxed and friendly. Some office politics and egos, but less than normal. Excellent job security (which can be an issue, see below). Upper management is competent. Most of the issues below are getting better, but still there.
Cons
A lot of talent is wasted. The culture has 3 interconnected issues: 1) Seniority and education are key to promotion and pay 2) Underperformers almost never get fired 3) Years of service='Experience', with no consideration of performance Its not as bad as some union shops, but you see too much top talent on the bottom rung and a lot of complacent, mediocre middle managers. Lots of old dogs that stopped developing and manage based on how it was 20+ years ago. The web and IT are just getting out of the 90's. Too many contractors, lots of waste. Funny considering they are a technology company in Silicon Valley. A PhD in Chem/Biochem and a few years experience qualifies you for almost any position. Not much respect for other disciplines, even engineers. Risk aversion can be so extreme that it stifles innovation and improvement.