Pros
The performance of the team is clearly aligned with the overall success (or failure…it is a startup after all) of the company. Every person's contributions count and most of the team knows the where and how of their impact. This is both intimidating and exhilarating. Management expectations (and coworkers’ expectations of each other) are driving everybody to their limits in knowledge, skill, ability, and effort. Both management and coworkers are asking for more. Again, this is dual sided - it is exhausting and empowering. I have been with two start-up during the course of my (limited) career. My first startup experience was kind of embarrassing; it failed and my inability to find a meaningful way to contribute caused me to go back to school to realign my skill sets with what I thought I wanted to pursue. In the case of the second startup, Circuit Clinical, I feel like I am going to be able to leave everything on the table. Regardless of the outcome of this experience, I feel like am truly honing existing skills and rapidly accumulating new ones. Finally, I am super jazzed to be taking a crack at these problems, with these people.
Cons
Uncertainty and slightly distorted work-life balance; but that feels more like a feature as opposed to a bug.