Pros
Growing company, so there was a ton of opportunity if you played your cards right Huge career launcher - I got my dream job with my skills gained here, and it only took me about a week on the market to get several job offers. Good benefits, coworkers became like family even after the office closed. For the first year or so, work was really really fun and rewarding.
Cons
At the time there was bad communication between board members and executives but I heard that is being sorted out and attributed to growing pains. It seemed like everyone wore rose colored glasses...there was a cult-like feeling sometimes the way the troops were rallied at All Hands meetings (I think this is a normal Silicon Valley strategy though). It wasn't uncommon to work 50 - 60hrs per week 'for the greater good'. It was inherently sexist there, there were fewer men workers but they were in management positions and made a ridiculously high salary comparative to all of the female 'worker bees'.