Pros
Exposure to exciting projects and some great clients. Can be fun to be part of a large organization that is well-known.
Cons
There are a lot of people that have been employed there for years and are not good at their jobs. The company does not think about the long term impact of decisions that it makes and each fiscal year, each team has to shift their energy to satisfy what is on Ballmer's agenda. This leads to dissatisfied partners and clients and wasted time and money by teams that have spent a year building up a program just to have it all thrown away. Just think what MS could do if they had a vision and stuck to it. Overall - an extremely toxic environment with unethical people that will do what ever they need to in order to move up in the organization and get recognition.