Pros
Benefits, community, opportunity to learn new technologies. It is all about software and you work with really smart people. You have your own office. I am a woman and I like that Microsoft partners with women organizations.
Cons
Too political. If you want to have a career at Microsoft you need to have a sponsor. It doesn't matter how good you are at what you do and how intelligent you are. It doesn't matter your reputation outside. You need to build a reputation inside and always have one or more sponsors. It is also a very competitive environment and they privilege competitiveness over collaboration besides they say and "promote" the contrary. That can become very stressful because you have to work really hard and many of your peers will try to discredit you and that gets worse when the review period is closer. Microsoft also doesn't do a good job regarding diversity. I see it as a quite homogeneous ecosystem. In many of the groups (I won't say all because I only worked in a few) most of the employees are Indian males and the very few women are mostly Indian or Arabian and they are usually shy, don't speak up (maybe that explains why there are so few senior women). I am a woman coming from a more liberal culture and I really feel intimidated by this. Don't take me wrong, I don't have anything against any particular culture, it is just the lack of diversity that I don't like. I don't feel I have much in common with most of the people I work/worked with here.