Pros
Microsoft is interesting in that it presents some of the most difficult challenges a huge company faces in this era. I found many of Microsoft's employees particularly outside of Redmond to be stellar and delightful collaborators.
Cons
The culture is BROKEN. This place will suck the soul out of you. I think all of Microsoft's challenges essentially are a result of a company not growing up. It is inbred, the senior management layer is peopled with individuals who 1. likely started their career at MS in 198X or 199X, and 2. haven't seen what's going on in the rest of the world. They all have the same orthodoxies and it's killing them. A huge piece of not growing up is holding on to the management philosophy that essentially pits people against each other to survive and be promoted. Microsoft never gets 1+1=3 because there's really no such thing as a team there.