Pros
It's kind of the only gig in town in this industry. If you're interested in marketing or advertising, there are corporate jobs, and there's TBA. And they do from time to time produce interesting work. Oh, and there's lots of free beer.
Cons
Management is uncommunicative to a fault. Poor organization from top to bottom. Pretty terrible at client management. For example: It's very common for the agency to take orders from clients, implement a really terrible strategy. Then, when the client complains to the CEO, he tends to throw his own team under the bus and blame them, when the problem was a bad strategy. There's also a tendency to over-serve clients and just write off expenses. The business only stays afloat due to very low salaries for the bulk of the employees.