Pros
Broad mix of clients so there are opportunities to work on a wide variety of brands and projects. 4-day work weeks. It's an all-employee owned agency so when the agency is doing well everybody benefits. Relatively flat structure. And great people. Smart. Passionate about the work. Not arrogant. It's the kind of place where jerks would feel out-of-place.
Cons
None, really. The pace is fast and expectations are high, but that is the case with any agency. It is rare to find an advertising agency like this. Which is why there is relatively little turnover.