Vantaggi
An opportunity to be a part of something big. (Not just in company size, but in the projects they take on.) MS has the resources to invest in cutting edge tech. And, chances are your project/product will impact millions of users. The culture is pleasantly surreal compared to the rest of the corporate world: (Casual, private offices, diverse, free soda, MS software free for work use and cheap for personal, great buildings and cafeterias.) They make you so comfortable, the line between work and home get blurred.) In general, the people you will work with, regardless of team, are some of the smartest and most job-focused you will meet in your life. Going to any other company after MS will seem like stepping into Mayberry (simpler folk, moving slower). The benefits package is awesome, I'd guess in the top 1% of all companies. And the non-tangible benefit is an aura of respect you get when outsiders know you as an MS employee (of course, you're thinking: "I'm one of 90,000; what's the big deal?")
Svantaggi
Sometimes the politics at MS becomes over-whelming. Their emphasis on performance for compensation and promotion gives a lot of power to direct and up-line managers. One would hope the most committed employees and those that did the most for the product are rewarded. But in reality, it is the brownnosers and drinking buddies of the right people that move up the stack. MS pays big lip-service to flexible/remote work arrangements but it is mostly talk. This is a company that expects you there in person most of the time. Combine that with the long work hours, and it is the ideal job for young single people and divorcees.