Pros
Meritocracy, good people, good work/life balance. some excellent projects and thought-leading work. Some teams extremely dynamic, aggressive and undoubtedly world-class. Almost all people have time for you with a big cultural emhasis on mentoring, coaching and collaboration. As a result even the most time-pressed and inspiring leaders find time to speak with the best people.
Cons
Sometimes not aggressive enough so promotion opportunties become difficult after middle management. Can be bueraucratic.and too "by the book". Offices not great. Sometimes it doesn't feel like you're working in a tier-1 company. Sometimes doesn't raise the bar high enough and laggards can get away with poor performance over a number of years before being finally found out.