Pros
Adds a strong line to your resume. Free lunch and snacks. Big client projects. Great connections.
Cons
It really depends on which partner's team you are in, but they often treat designers as tools to bring good work for them rather than valuing them. Pay is very low compared to other companies with slow, infrequent and minimal raise. Timelines are super compressed and you are expected to do the amount of work 3 desingers would do in other companies. And of course you must produce strong work that meet their standards, so the pressure is high. Also a lot of the designers are kept as interns or freelancers for a long time before going full time. Overall it feels best to gather a few strong portfolio projects quickly and move on.