I spent a few days at Riot for one of their hackathons. First of all, the entire space feels like a video game inspired theme park. It's really unlike anything I've seen before. While I can't speak to what the daily routine looks like, I was blown away by how passionate Rioters were about shipping great software and UX. I spoke with one of the lead designers for the Ezreal re-work, and it's shocking to learn just how much effort goes into every minor detail. They do everything in their power to ensure users love the product. That's not the kind of culture you find at your typical software shop.

Also, Riot has an excellent developer community and API[0]. Riot believes that the community, not just the engineering staff, makes the product great. So, a lot of effort goes into making sure 3rd party developers can work with the LoL brand.

[0] https://developer.riotgames.com