Pros
Not anything. They lure you with stuff like an onsite visit and the best devices, but they are at a higher cost than you think.
Cons
No transparency by management. Even AMA sessions seem to be moderated to not ask any questions—no platform for hiding the identify so that you don't ask. No job security—on a fine morning you'll be asked to leave and your access will be revoked in the next 10 minutes. They hire you for different skillsets, give you different things to work on, and execute mastery immediately in complex client projects. This is bizarre, then they blame you. Well, even if its management unrealistic commitment, you will suffer anyway. Don't join if you are not a javascript person. And the bench is too bloodsucking and a place of extreme micromanagement.