That said, the way that Microsoft has been dealing with its extreme uncoolness lately has been by paying salaries that are far above market. With very few exceptions, every time I've tried to recruit a Microsoft veteran to a startup, they've started to pull out the spreadsheets and given me complicated sob stories about how they can make $1m in the next three years if they stay at Microsoft, whereas I'm only offering them, eh, a few % of a hot startup.
The bottom line is that spending a lot of time at Microsoft could very well ruin you for startups.
Even though I did it that way, there are two different ways of thinking about your career, and if you're REALLY a startup person, you're not going to be hedging bets by serving out your 5 year Microsoft prison sentence. If you're telling yourself that as soon as you're fully vested you'll leave, you have failed to take into account the new incentives that Microsoft will put in front of you by the end of the fifth year. And eventually you're going to be stuck in the $300,000/year treadmill at a life-sucking anonymous job with no chance of ever hitting it big (or making an impact on the world).