Pros
There is an incredible amount of exposure here. Early on I was working on projects that mattered and getting in front of people that probably would have taken years of relationship building to foster elsewhere. Aside from high visibility and exposure you get a lot of ownership. Not just helping out on someone else's work, but actually building things and seeing the impact. The pace is high but so is the opportunity. If you're someone who likes being pushed and wants to grow quickly, there's a lot here for you. I've learned more in my time here than I expected to, and I'm definitely not the same person I was when I started.
Cons
The pace and expectations aren't for everyone. There's a lot of opportunity here but you need to be comfortable with ambiguity and taking ownership.