Pros
Crazy good learning opportunity, they gave ridiculous amounts of responsibility to people who can prove themselves. I didn't actually have formal qualifications in my field but they gave their people a the chance to sink or swim, which I did thankfully. Compared to my friends in similar jobs I could honestly say I've learned 10x more than any of them did.
Cons
If you're from corporate and that's all you've ever known, don't even bother - I've seen many corporate types struggle and quit. Everything about the company will be backwards for you. It's growing really fast - too fast to get comfy. you role will change, your required skillset will change, your learning requirements will change, your team will change, your priorities will change (in line with OKRs). it's like they're filtering for a certain hyper growth friendly team and they are losing nice people who just can't keep up - in fact those people hate it. That's actually a little depressing because everyone in the team can see . Some of those people aren't necassarily poor performers too, they're just at a different life stages. I don't think management's found a way to cater for it or they've designed it this way. Oh and they moved into too big an office, I liked the old days of being together in a small one and most would agree.