Pros
I've been at my share of large, established companies as well as start-ups, and Fullpower offers many of the best aspects of both: innovative technology that has the potential to change the industry, employees that are truly excited about what they do, and possibly most important, the stability of solid funding and proven leadership. The CEO in particular has an amazing track record of founding successful companies, and I quickly came to respect his intuition about products and market trends.
And while everyone certainly works hard, it's a relatively relaxed work environment. Many people bring their dogs to the office, and employees take breaks for crossword puzzles or to take walks along the nearby San Lorenzo river or Downtown. Every Wednesday afternoon many people go to the Farmers' Market a block away for lunch and fresh produce. As far as location, it really doesn't get any better.
A fun perk is the sailing races: employees can bring family and friends on a beautiful sailboat for pizza and fun on the Monterey Bay every Wednesday night during the summer. I went several times last year and couldn't believe this was just part of what Fullpower offers!
Cons
I do miss some of the more structured opportunities for continued learning that I had at larger companies, but management is generally very supportive of attending conferences and such to keep current in your field.