Pros
The level of talent is high, and colleagues' commitment to having a positive impact in the world is impressive. Most team members have impressive backgrounds, but are generally humble and approachable - willing to engage and share ideas. There are also a wide variety of backgrounds, which makes working together more interesting. I also think there is a high level of mission and organizational buy-in, which is supported by the employee ownership plan (a nice feature of comp, especially if you stay long-term).
Cons
Especially in the mid-levels you can be stretched to manage a team, carry some business development obligations, and manage upward to firm leadership. The plus side is that even at a relatively early stage you're involved in practice-level (and even firm-level decisions) which helps as you try to find your way to a senior-level in the firm (often by owning a new geography or practice area).