Pros
Its a market leader with intelligent people working at the company. If you want to learn and be challenged, then you will enjoy working here. To build on this, there can defintiely be a clique-like mentality in some groups. These can be beneficial and detrimental at the same time. If you prove yourself quickly as a comptent, hard-working individual, then you will find yourself surounded by people that are interested in seeing you succeed. If you do not prove yourself in this manner, you will undoubtedly find yourself in limbo or on your way out, and probably surounded by people that share your same fate.
Cons
They have a tendency to retain the fat a bit too long. I know there is protocal to all employee management; however, because a large part of our jobs are working with clients, this could cause long-term damage to the positive client relationships that make this company a market leader. Another downside to this company is that there is a definite political nature at Advent. I have experienced that achieving objectives in an efficient manner could sometimes be bottlenecked by political approvals. This does not occur the majority of the time and I can't generalize this across the entire organizaiton, but I have experienced this.