Know what you are getting into...
Pros
Management is tremendously smart, and willing to spend on technology, people, and processes. They have the big picture in mind, they are taking all the steps needed to get there the right way, and working their butts off along side of, if not harder than everyone below them. They are trying everything to keep people motivated - free drinks, snacks, dinners/lunches, flexible schedules (as long as you are willing to still work +10 hours a day, after you prove yourself, they don't care too much about where you do it from), they are spending on outsourcing until they can staff up positions, spending on hiring true experts in their respective fields at high cost and at fairly low management levels.
Cons
A new guy said it was like a minnow trying to swallow a whale. A very well rich (Blackstone), smart (Gramercy Management), resourceful minnow... so there are lots of problems and low hanging fruit and not enough people to fix/harvest it all. A lot of non-routine issues arise. So everyone (in accounting) is working like dogs just to keep everything going.