Pros
Riot Games is an amazing company to work at. You get to interact with some of the brightest minds in gaming and everyone is always up for discussion. There is very little sense of hierarchy. Not that you don't have someone that guides you, mentor you and pushes you to achieve what you can do and even more, but more that logic rather than seniority guides decisions. It's also not a place where seniority matters a lot. Of course time helps you illustrate your talents, but there is no time required to grow. The only thing that limits your professional growth is the pace at which you can learn to be what you want to be next. In a way, when you enter Riot Games, you are the entrepreneur of your own success and of the company's success. The Culture within Riot is really amazing, and highly enjoyable. I need to be intellectually challenged constantly, and I can count on all of my coworkers (which I consider my friends as well for a big part of them) to bring new problems that everyone can reflect on, although in the end one person or one group is going to be tasked to solve it. There is also a culture of constructive feedback that allows everyone to evolve constantly and that goes both ways. I had very bad feedback from a team, and instead of just putting the blame on me, my career mentor took the time to investigate and get deeper within the problem, which ended up by giving mutual feedback in both directions in a constructive way.
Kontras
Riot Games has grown immensely in the past 3 years. This means that the structure in which you evolve is not always spot on to the theory of what higher management wants it to be. There are a lot of organizational challenges that need to be fixed, and having a very bottom-heavy company means that it's often easier to ignore an organizational problem for most Rioters than to actually tackle it on your way to the objectives that really matter. Riot Games is the worst company if you want a job in which you can just do your 8 hours a day and disconnect. The problems that we face are intellectually sticky, and ambition is a must have if you want to be part of the Riot Team (not family). This is a place to grow and evolve, not just a place to work at. Another issue is that the international offices have grown so fast and emerged from the ground at such a pace that in a lot of case there is a lack of understanding / communication with international offices.