Pros
I am relatively new at the firm but I have found everyone, at all levels, to be extremely welcoming and positive. The company culture is entrepreneurial, gritty, curious, and collaborative. Leadership is very open and accessible, and doesn't have big egos. There isn't a lot of politics or posturing. People are generally open to criticism and not defensive. Most everyone seems primarily focused on finding the right answer for clients, growing the firm, and growing their careers.
Cons
The company is growing quickly, so there is lots of change -- in strategy, in leadership, in the product, etc. If you like change, you will thrive. If you are bothered by change, then this is probably not the place for you.