Pros
On one of the smaller teams with one of the newer applications, there was sort of a feeling of being a small company within a huge company, which I enjoyed. I loved my team. I felt like everyone around me was competent and knew their stuff, and they were all both helpful and friendly. After leaving the company a few years ago, several of my friendships survived despite moving out of state, and I'm very glad to have met them. My boss was fantastic. Not everyone's is, but I've heard mostly good things about other bosses too. Becoming a functional area expert was pretty neat--knowing my piece well and how it interlinked with everyone else's work. The flattened hierarchy where everyone should feel comfortable reaching out to everyone else made for a pretty good environment. Food is delicious, and walking around campus is pretty nice.
Cons
There's no getting around the fact that the large auditoriums and mandatory monthly meetings have this cult-like, megachurch vibe to it. It isn't helped by the fact that people talk about "Epic Culture" and "What it means to be Epic". It's cool if you're crazy about team spirit, but overall pretty weird. There becomes this strange spectrum that hovers around 3 groups: Kool-Aid Drinkers, the Just Here to Work, and the Constantly Cringing. They pretty much have a policy of push as much work onto a person as they can until that person learns to say No. My boss respected my no, but it took me almost 2 years of 55+ hour weeks to learn that I could say that. After that, I stuck to 40-45 hours/week 90% of the time. The level of feedback wasn't that present so I spent a lot of time spinning around in imposter syndrome until I realized I was doing fine. A lot of the technologies are outdated or specific to Epic, which is unfortunate. They're doing their best to update, but as a large company, it's difficult for them to navigate transitioning to better tech with all the demands of satisfying so many customers.