Vantaggi
Great benefits, incredibly smart people, worldwide impact. You will have all the tools you need to do a great job if you have the energy and motivation. You can meet with anyone in the company if you can find time; everyone is happy to help each other out, to give feedback, to talk about career advancement. You will be paid better than at other similar companies. An internship at MSR is more structured and more productive than at IBM or Google; you will also be encouraged to publish.
Svantaggi
The commutes around Redmond are horrible. There are no trains or light rail options; you must be on the road whether in your car, a bus, a carpool, on a bike or on foot. From near the 520 bridge in Seattle, the commute takes between 30 and 120 minutes. Microsoft's "hero" culture can be tough for new employees to navigate. Shyness will get you nowhere.