Pros
Free food, on occasion, a christmas party that hasn't been litigated out of existence yet. They hire good people, some feel compelled to stay.
Cons
Every account in general run like a sweatshop. Useless old white management they are trying to change but is immovable in the field offices. Rampant drug and alcohol abuse. Alcoholism is extremely common and is codified as part of the corporate culture. Agency losses are constant and made up for by free work from existing employees until they too quit. If you're new, this is going to be you too. The agency suffers from an overall rudderless management scheme for years in which sexual predators, alcoholics, professional jerks and the generally useless survive every purge but lower level employees are sacked without reviews.