Vantaggi
By far the biggest benefit for me is the opportunity to work with peers who really are the best and the brightest. At previous companies I have worked at, I would frequently get frustrated with the level of incompetence of others i had to work with. With very few exceptions, most everyone at MS has a right to be there. I can't say enough about the opportunity to transfer across divisions and disciplines if you are motivated to do so. Work/life balance goes in cycles, but in general is ok.
Svantaggi
Bureaucratic bloat has impacted the ability for most teams to be agile. For a technology company, it's amazing that there is almost no acceptace of remote/virtual work. While working remote/telecomutting, part time, etc is given alot of lip service it's almost always career limiting.