Pros
AP was a positive experience for me. From my experience, AP is a meritocracy. Strong performers are rewarded with a fast promotion track and increased responsibility. This was great because I learned much very quickly and I was promoted quickly and constantly challenged. AP has international offices outside of the US and strong performers were encouraged to rotate to offices in Sinapore and Ireland. That was appreciated even though my personal circumstances didn't allow me to take advantage of the travel and exposure to foreign markets. Co-workers are generally good people, friendly and welcoming. Co-workers are mostly friendly and have willingness to work as a team. The business is interesting and I was lucky to have the chance to work with a variety of industries. AP allows you to learn alot about marketing analysis and marketing mix modeling and forecasting and consulting.
Cons
The flipside to fast promotions and variety of clients is a lot of work. I understood that coming in (I did an internship at a Big 4 accounting firm while I was in school, and AP is tame compared to that). AP is very client-focused firm and managers do not like to say "NO" to client demands, and some clients are too demanding. Again, this is not different than the "Big 4" accounting firm that I interned at during college. But, as the old American business mantra goes: "The customer is always right" and AP sticks to that ideal. I found that some managers are stronger than others when it comes to spending time on training. So, experiences may vary due to who your manager is.