Vantaggi
The name of Microsoft on your CV is great to have. There is a supportive collegiate atmoshere where the employees help out each other without the dog-eat-dog atmoshere of other companies. There is a fantastic work-life balance where time off is not just permitted but promoted. They value employees and their families. The benefits package is flexible and is very reasonable - perhaps the best I have had in my career to date. The tools you get to do your job are cool. They are very focused on being "green".
Svantaggi
Microsoft do not pay very well. It is a product-focused sales organisation (if you are in the Sales, Marketing and Services Group) when it should be embracing "Solution" selling and a consultative approach to its customers. It is now focused on short-term revenue targets and drive short-term behaviour. The upper management team is OK but somewhat ineffective; the middle-managers tend to micro-manage their team based on weekly revenue reporting. It is anticipated that you self-serve when it comes to knowledge about products etc. Email overload and too many meetings (but this is common in large comanies).