Pros
It is a challenging place, we are the leaders in so many different markets, but yet we try to innovate. It is fun and MIcrosoft tries to give you all the tools necessary to complete and live your passion. Working with smart people is incredibly challenging and rewarding too. I wake up in the morning and I don't dread my day (on most cases). In addition, the the benefits are incredible, small perks that make you feel like you can concentrate on your work. The best thing about Microsoft, however, is that you can really try to live your dreams. The opportunity to move around, change position, try something else is to me priceless.
Cons
There are mainly three things. One is the location. Microsoft is Redmond, there is really no other place like it. You can work in the subs but less interesting jobs really force you to move to headquarters. And Redmond is close to Seattle, which is a great city, but the rainy city really lives up to its name. hte second is the corp culture, which I am sure it's great, but the incredible amoount of meetings, and the slow process of getting things done cam be frustrating at times. Third and last, is the tendency to have managers who are really into their career. I know that different people have different experience, but the desire to achieve commitments is the highest priority, while sometimes doing things differently is not as rewarded.