Company: Microsoft
Date: 2012-12-24
Overall rating: 3/5
Employment status: former
Experience level: Junior

hit it and quit it
Pros: Valuable political and product design skills that will serve you well as long as they don't poison the culture at future employers.  Stay there long enough to get a promotion or two, see how a big company ships large complicated pieces of software then leave.
Cons: There is no company mission except make more money.  Career management basically means developing a useless skill of positioning yourself to have "visibility" and "impact".  Especially pronounced at GPM or equivalent level.

If you're in the big groups (Windows/Office/STB), the build systems knowledge doesn't carry over very well.  They use a hacked up version of perforce for source control and branching and integration is extremely expensive.  Continuous integration simply isn't feasible yet on a system of that size (though private builds and replacing individual DLLs at certain layers is possible).