Pros
Working with a robust sales team, talented designers and programmers, and in the mobile space is interesting. Interacting with players and real Americans is really cool. Occasional company parties are fun.
Cons
Not really a start up, it's been around for many years, and has all the negatives of a startup (bad work life balance, lots of crunch, poor organization) and all the negatives of a corporate, large company (very strict office hours, strict vacation time, top down management structure). They'll use anything to excuse the bad work environment. Usually "we're growing" and/or "we're a startup" if you try to bring up any issues, instead of listening to the employees. They seem to fire people without any warning or reason. No room for growth, even people that were there for years got paltry raises. Terrible communication between employees and management. HR is almost non-existent and hard to get a hold of. Top-down structure. Also not really a games studio. The one "game" they make is a pretty lame scratch-off / lottery app. They expect everyone to put in a lot of overtime, esp the engineers.