Pros
Wonderful, smart, fun people who get a lot done. Many like to hang out often after work. Lean teams, which mean you'll get to learn and do so much here. Technologies and scale that impress people inside and outside the company. Many things don't have a process in place, so if you make a good case to your manager, you can probably get it. Business continues to grow constantly, so it's exciting to be part of. Culture is built ground-up. Employees start traditions instead of management sponsoring things they think people will like. Not much politics. A lot of employees have been here many years. This is impressive for a small company in this market. Spends money carefully.
Cons
The office isn't as nice as other tech companies in the area, but we're moving to a new office in a few months which should address this. Salaries are lower than some other companies. All these things are probably on purpose though. A lot of people respect executive leadership for not buying into the hype and taking in more funding just because other companies are doing it.