Pros
Pros: As an intern: Great benefits (Geared towards college students, which basically means free stuff like mini fridges, shirts, zunes, etc). As far as DevDiv is concerned (Developer Division), I was very happy with how my teamed worked, and treated interns. Did their best to help you learn, such as even sending interns to conferences (which I was quite surprised about). If I had to do it again, I would defiantly accept the offer. What was really awesome was working on a project that would actually get released to millions of users, which is something that can't usually be said for most places. The random events that they host for interns is the best part. Make sure to go to as many as you can.
Cons
Cons: Hide what it is really like to interns (which makes sense, but still...). Horror stories are heard about teams who treat their interns badly, or give them projects that are basically useless. Also pressure you about taking an offer at the end of the internship (which you want to be paid 10,000 dollars less is not a very good idea). Also is prevalent that they have an email discussion list that was made to distract interns from doing work. Kind've backstabbity in my opinion. Not very impressed with the idea. If they would fix a lot of these issues, it would be much better.