Pros
Mostly bright, enthusiastic people. As a start up the company had an energy and a dynamism that I've not experienced before. Compensation is above average. Free snacks and drinks.
Cons
The energy and dynamism is now largely gone as the company has expanded. The products are the best, they're also increasingly complex and training of customers / partners hasn't kept pace resulting in customers being unhappy and sales becoming more difficult. Professional services aren't used as much as they should be. Management positions are filled from within, so none of the 1st line of management appear to have significant management experience when they become managers. Some management overly inclined to micromanage. No clear career path, promotions are based on politics more than merit. Moving horizontally is problematic. Some senior management are tempestuous and inapproachable.