Pros
Supportive management. The CEO and management are good guys: You will feel a welcome part of the team, and you will want to help them succeed further. My manager was also very supportive when I was going through some health issues. They upgraded our machines and monitors to very nippy ones when we requested them. They gave me time off for training when I requested it. There were no company politics.
I left primarily because the nature of my job had changed (less need for what I enjoyed doing) and as a result it no longer appealed to any more.
We had wine together on Fridays which was really nice, and most people there were very friendly.
Cons
Pay was on the low side (as it was a startup) - but now they've been acquired for a while so perhaps it's a different situation.