Pros
World class peers Great management (in software at least) Good stock sharing Huge opportunity to use many different technologies Looks great on a resume An absolute beehive of activity (if you like that kind of thing) No expense spared on desks/computers/monitors/chairs Amazing food at restaurant Mgt is flexible on hours, and if you need to go to a doctor or something.
Cons
The work/life balance is not as bad as its reputation. Everyone I saw that was really busting the hours was doing it to themself. It is because when your peers/friends are working really hard, you will tend to do the same thing. It is rather crowded these days. And if you don't like an open office cubicle environment, that may be a problem .... there is a ton of stuff going on all the time.