Pros
Lots of incredibly talented specialists who are fun to work with on a team. The office space and extra curricular activities are great if you are young/single...seems like overkill if you aren't. Working at a game company and playing sometimes during the day is great.
Cons
There is a constant turn-over of leadership with little direction of the vision. As the company grows it is starting to become "just like any other company" by chasing after $s and making quick, short-term bets. There is a high level of nepotism still at the company which means people who were great during the start-up phase are underwater now that the company is larger. Also, until more titles come out there isn't really any room for career growth. The organization is flat which also means there aren't any open positions as LoL is pretty mature in its structure. I had people on my team who had been there for 3+ years who were bursting for change but couldn't afford to move. Finally, the culture of feedback is completely broken. There are no clear expectations or metrics. You have two choices...spend all day having one-on-ones to butter up your superiors or spend time doing your job. I honestly don't know how any work gets done with so many coffee chats during the day. All bark and no bite.