Pros
very casual environment and easy work. Lots of food, snack, and treats provided if your game makes them money. Its totally out of your control if your game makes money, but if it happens to make a ton you get all kinds of goodies. I recommend it only to friends because its easy and good money.
Cons
You have to abandon any real pride at the door if you are an artist and work here. The pay is great and the work and workload is easy, but the games you work on are hideous, the gameplay is bad, and dont try and change anything because everyone in charge thinks what they are working on is the most amazing and stunning thing ever, its kind of hilarious. Draw your pizza, cows, trees in the bland clipart style they demand, and you will be fine. Its also a total brofest working there, lots of graphic designers and failed animators masking as illustrators with art directors that have no actual artistic talent, immediately realized that is why things look the way they do with anything zynga does. Any talent is repressed and its kinda tragic to see someone new with actual skills take charge only to get knocked down and return to whats easy. Every game while working there was just ripping off another studios game, then thinking of the way to make the most money till users lost interest and then the game team would close up and get outsourced while you moved on to the next boring thing. I had some amazing artists that went on to do stunning work at other companies, but zynga beats you down so you just stop caring and do what the boss wants.