Pros
Great benefits, security, but experience 100 percent dependent on your manager and workgroup. There is no such thing as One Microsoft from a personal experience perspective. If you don't like your group, move. It's a well resourced company with a lot of smart people and some of the world's most interesting challenges to work on. Good opportunity to work globally and learn a ton about business if in the right role.
Cons
Massive change at mid-senior management level right now. Very little direction can make it hard to see big picture at the functional and workgroup level. All old systems seem to be scrapped and tagged "bad" without anything to replace them which can be touch with such a large beast to maneuver, new CEO, lots of new people in charge. Will take another year for changes to net out to really evaluate what it's like as a place to work. Disappointing to see last round of layoffs - lots of great people and not a lot of explanation. Morale at risk in many groups.