Pros
It has several great systems in place and was a great company in the past. If you are a just starting your career, Microsoft is a great place to work for two years. You can learn a lot about how a big company works and take all that knowledge with you. Technology wise, they only use Microsoft software which is bad if you want to join other technology company that maybe built on open source software.
Cons
It kills your potential. To succeed in Microsoft the primary skill you need is perception management. That means you need to be a great politician. If you are busy working and doing the right thing for the company without playing the game, be sure some else will take the credit for your work. Actually doing the right thing for the company is a bad thing for you. Your focus should be only in growing your manager’s kingdom that may include sabotaging their competition and doing what is wrong for the company. The company is setup to hire young people and get rid of the old. So you have a medical plan that you probably won’t use much anyway. Since 2013, the medical plan is not that great anymore. In the end, keep your eye on the ball which is to maximize the benefits you can get out of Microsoft. If you spend your time in doing the right thing, do not expect the same in return. Do it knowing you will not get the same in return.