Pros
Good pay, outstanding benefits, incredily smart people, and leading edge software technology and processes. I know some parts of Microsoft have their own ecosystems and processes which can be considered old school, but there's many facets of the company that are ran like a start-up where managements job is to just remove road blocks and let the dev/test/pm chain innovate. The company is so huge there are opportunities to work on whatever you want. Employee training is top notch, and you are free to change your career path as you want. The work life balance is very good, and the review process is mostly fair and honest. I haven't had any problems with politics, but that doesn't mean the system is perfect. Compared to the other big popular software houses (i.e. Google, Amazon, Facebook, Apple), I feel that Microsoft is probably the best company to stick with and have a brilliant career. Many people I work with came from Google and Amazon and are much happier with Microsoft.
Cons
The company is huge and it's not uniformly ran. Make sure you understand the dynamics and culture of the team you're thinking of working with. It can either be a horrible experience of an awesome one. Good news is if you're not happy, there's plenty of other divisions and groups to work for. Another con is Microsoft is famous for its BGHS (Big Giant Head Syndrome). Meetings are always rat-hole'd by smarty pants that feel it's important to argue and debate details to the point that you'll be lucky to get through 2-3 slides of your presentation. Some people are difficult to work with because they are very extroverted and opinionated. Having strong communication skills is paramount to surviving here.