Pros
Flexible schedule. You pick your hours as long as you are there for "core hours" (1-5pm). High quality clients. Owner makes sure that he chooses only clients that are reasonable and good to work with. Atmosphere is very positive, easy going. Coworkers enjoy helping one another. New hires--even the green ones--are considered equal members of the team right away. No sense of discrimination based on experience/gender/language preferences/whatever. 401(k) allows you to trade as you wish (I want to trade stock options so I am not interested in picking mutual funds/ETFs)
Cons
There are only two women: developer and hr. Everyone else (all ~30 of them) are guys. There is no transparency about finding out how much you should be asking to be paid. My manager says he doesn't know what the developers on his team are making. Only the owner knows this. (Though there is talk of this changing, maybe) Matches only 2% for 401(k). (They match half of your contribution, up to 4%) They only allow you to work in the office. Working from home is allowed only in rare circumstances. This isn't an issue with me; I wouldn't trust myself to stay on task at home anyways, but I felt like this should be brought up.