Pros
If you want to always work on the cutting edge technologies, then Microsoft is a great place to work. You'll always be surrounded by incredibly smart people who are passionate about their work. Microsoft is a place where your opinion matters and where your ideas will be given merit. The work life balance is great. Flexible work hours and the ability to work from home depending upon role obviously, is fantastic. The benefits are still outstanding when compared to other Fortune 500 companies. But they are not what they used to be, even from a couple of years ago. The culture has also suffered a bit over time. But in today's PC world that is to be expected I guess. Overall I would highly recommend Microsoft to anyone. It is today and will continue to be one of the leading tech companies globally. And working for that kind of company is exciting and very rewarding.
Cons
The stack rank system used to determine where employees fit in to the overall work force is flawed at best, and leaves a lot to be desired at the least. A quick Bing search will tell you all that you need to know about this system from both current and former employees. The higher that you progress in your career, it is sometimes that much harder to get noticed. One reason for this is that at Microsoft, the bar to just get a job here is so high, that you are competing with the best of the best for opportunities, and advancement. See stack rank above.