Pros
Very smart people, hard working teams, great reputation in the advertising industry. Perfect resume builder. Nice office with good coffee perks and they throw awesome holiday parties.
Cons
If you're a junior employee here, don't expect to move up fast unless you're male. I hate saying that, but it's very true. They don't negotiate on pay, and one senior manager once said to me verbatim "I promoted someone and got burned, so I'm going to halt promotions for while." How does that make logical sense? They will expect absolute loyalty and for you to 'volunteer' your time, but won't show you the same consideration. During review it has beens said that while you've done excellent, that's to be expected so you will only receive a 'good' performance review. If you want to receive the 'excellent' review, you will need to work a lot of overtime. As you can see the burn out rate is really high and there are periods of mass exodus.