Pros
I have had the privilege of working at one of the largest companies in the Seattle area (Microsoft) and one of the smallest (Net-Inspect). I cannot say enough positive things about Net-Inspect. The CEO has given me a significant amount of responsibility and the freedom to take risks and make major decisions on my own. Every team member deeply cares about the work that they do, the customers that we serve, and the users that use our software on a daily basis. We all work incredibly hard but also find our work incredibly rewarding. It has been exciting watching the company grow the past two years, and I am confident it will continue to grow in the years to come.
Cons
At a small company like Net-Inspect it becomes very obvious if you are not carrying your weight/contributing to the team. Fortunately that helps attract the right people -- self-managed, ambitious, hard working people.