Vantaggi
Accenture is a great place to work, they have excellent benefits. Their compensation packages seem to be pretty competitive with the industry. There are lots of international opportunties if you have the right skills and expertise. The people at Accenture are usually highly motivated and the teams out in the field (true consultants) are some of the sharpest people I have ever worked with. They have a decent knowledge exchange mechanism in place for you to look for assets and IP that the firm has produced. It is a strong company that is being run by a leader (Bill Green) that is well respected across the firm.
Svantaggi
It is a very BIG company, and it is very easy to get lost in the maze. It is more "relationship" based than it should be given its size (people tend to gravitiate to what they know or what they have used in the past, regardless of how assets have evolved, or who might have a better set of skills to do a job). It is a large organization and there are a lot of experts that can be wired into projects, but the old partner mentality of building up a pyramid of known entities and promoting those people after x years of service is still there, after all it is an "up or out" model. Lastly unless you "grew up" at Accenture, started from a fresh out of school analyst (or similar) it is difficult to break into a click or network. Bill Green may be a strong CEO, but the people 2-3 levels down might not be getting the total picture and aligning to Bill's direction.