Lacking support for mid-level career development
Pros
Great people and some interesting products to work on. They do a good job with onboarding people and making Microsoft seem like a great place to be, but a poor job at retaining talent and getting you from mid-level to senior.
Cons
Little direction for how to get to the next level, but a lot of push to get there. Too many managers show favoritism and repeatedly reward their favorite employees with the best feature work, which leaves everyone else doing 'laundry' tasks. Review system changes every 3-5 years, but is currently based on 'impact'. How 'impact' is defined is open to interpretation, so it may help or hurt you based on your deliverables for the year. Unfortunately, you have very little say on what you actually worked on, so just hope it was something considered 'impactful' enough to get a raise/bonus/promotion.