Pros
I work in engineering, so I can't speak for the rest of the organization, but Engineering is great. Here's why:
The Management:
Our manager (Matt) is excellent, and very hands-off. His role has more to do with support and representation to the rest of the C-level team than anything else. He fights for us to be able to do large-scale refactors on the codebase, which has been incredible in a job satisfaction sense. This has a lot to do with him having trust in us to get our work done, which we repay by actually getting our work done. It's a great relationship.
The Culture:
The AtScale culture is best described with a Starship Troopers quote: "Everyone fights, no one quits." Which is to say, as long as you're working and completing what needs to be done, no one is going to get on your case for anything trivial. The team here is extremely veteran, and as such, there is so much trust between everyone here. No one is afraid to ask for help from anyone else. PMs have a great relationship with Engineering because they were hired specifically because they understand engineering inside and out. Quality > Everything.
As for extracurriculars, we play board games almost every single lunch break. Love Letter and 7 Wonders are the current favorites, but there is an array of other things people like to play. Not just engineering either! Pretty much everyone at AtScale is very chill and easy to laugh, which makes for an extremely pleasant environment that I honestly kind of miss on longer vacations.
The Work:
At least in my job, the problems we solve are hard but also very engaging and interesting. Sometimes you gotta pull out the ol' hard work shovel and do some dirty-work to get something done that isn't so fun, but that is definitely the exception rather than the rule. We are encouraged to innovate and experiment with new technologies but with a very healthy "Where's the beef" veteran mindset to make sure we're extracting real value from them, as opposed to just chasing the flavor of the month.
Cons
AtScale is located in San Mateo, which doesn't have great BART access, and even worse access from the East Bay. Caltrain is an option from the city however. As an East Bay resident though, the commute can be pretty brutal (45m-1hr in the morning, 1hr-1hr15m in the evening).