Pros
I have to say I've was shocked by some of the negative reviews here. They don't describe the place I have been working for many years so I thought I ought to add my two cents. My experience is that you get out of it what you put in. I personally have gotten a lot out of it. I have been able to grow professionally and work on a wide variety of challenging projects. I've been sent to some great training seminars, but I've had to seek them out and ask to go. Management really cares about its employees and clients. The pay is competitive and they have always given me a pretty generous annual bonus. They understand that you have a life and allow people to work from home when needed. Sometimes you need to put in pretty long hours, but hey, this is advertising, it's kinda expected. The owners work as hard, or harder, than anyone. They have some new really talented people in senior positions that are making a positive mark on the company. Over the years, I have been able to continue learning from the people around me. The founding CEO recently stepped down after 30 years and passed the torch to the younger partners.
Cons
No one is going to hold your hand here. They expect you to have some initiative and be a self starter. If you need a lot of structure this probably isn't the place for you. There are sometimes communication breakdowns that can be frustrating.