Pros
You'll get to work for some very reputable clients. The founders are very well-connected, driven, and motivated. You'll also work alongside some very talented individuals and learn a lot from them. You will be in good communication with some very awesome people and make lasting connections at this agency. I do believe leadership genuinely cares about their team.
Cons
Depending on your role, you can expect to be constantly be in meetings with little time in between to do work besides preparing for these meetings. There are so many Slack channels and you can expect to be pinged all day. Some of the directors will reach out to as soon as they smell a whiff of a fire, and stress you out with messages even if you have it under control and are extremely busy. That's always going to be tough while you're in the middle of a client call - especially if they don't understand your channels and need everything spelled out for them. You may have to play a lot of defense to protect yourself. Unlimited PTO is described as a benefit, but not honored (which is the case at a lot of agencies, to be fair).