Pros
They entice you with an impressive host of perks from fully paid commuting costs, liberal teleworking policy, free food, fancy computers, corporate expense accounts and more. But do not be fooled! You will need all these things and more when you are working 60+ hour weeks to meet ridiculous deadlines or putting up with nonsense from your incompetent, belligerent co-workers.
Cons
As my headline said, the people are some of the worst human beings I've ever had the misfortune to work with. They might seem really friendly at first and put on a front about how much they care about you. But the same guy who is dropping dinner off at your house one day after your wife has a baby will turn around and throw you under the bus to save his own skin in front of your boss the very next day.