Pros
First off, I have been working at Riot for two years and I love it here. I have worked at two other triple A game developers. Riot is a company of gamers who place the players first! This is true in the development teams (like many game companies) and it is also true in sales, finance, people (HR) and upper management. Riot values the player and demands that its employees think of the player value of their actions. Riot is also a company that places a great deal of autonomy in small teams and individuals. Teams and individuals are given high level goals and are then empowered to find the best way to accomplish them. I have found Riot to strive for a good work life balance. I have worked on a weeked twice (aside from checking email on my phone) over two years. Longer days are not uncommon however although only once has that ever been explicit asked of me (there was a problem with the live service and I was happy to help).
Cons
Management is not always there to tell you explicitly what to do. I have seen people fail who really needed more help from management and they were left to long on their own. It is important if you come to Riot that you are self-aware of your weaknesses because management won't always be there. Listen to your peers as well they may not be your boss but they can give you important advice. At times the reporting structure has been especially overloaded with managers having 20+ reports. Life can be chaotic at Riot. Riot values action and judgement over process. This means that things are going to change. Very few people are on the same team a year after they joined. Sudden changes can happen where the company is rapidly responding to an external event. I have been on a plane with 24-hours notice.