Pros
You get to work with great people with some of the best clients on generally interesting projects. Vacation and personal time are top notch. Clients are resumé builders and there are more than a few knowledgeable staff to learn from.
Cons
Raises are slow to come and are very, VERY small when they do. After five years of award-winning work, zero negative marks and 50-hour work weeks, I've only received less than a 3% jump off of my starting salary. Employees walking in the door make 10-15% more than I make now with less responsibility than I have. When confronted about why I was turned down for a raise again this year (Of the 14 people submitted, only 7 were approved for raises.), I was informed that the turnover rate was too low to justify reconsidering salary obligations. Obviously, my job performance wasn't a factor in considering compensation.