Pros
The team was incredible and really supported each other in work life as well as considering our personal lives. Everyone was very helpful and willing to share knowledge. Everyone believed in the technology and the future of the company. The work itself was groundbreaking and in a lot of highly interesting areas of application in aerospace and energy.
Cons
Being a smaller company meant having to do things that perhaps weren't in the original job description or related to my area of expertise. That came with the benefit of learning new things I would never have learned elsewhere, but the con of having less time to hone skills in my area of specialty. Other than that, no big cons.