Vantaggi
Working at ACN helps you built strong overall skill set. The exposure to the different types of companies, projects in different department, gives you an opportunity to have great exposure to build understading in regards to what companies do and how to do things better. I am extremely glad to have worked for ACN, as the learning experience of working there tought me a great deal.
Svantaggi
At ACN you should expect to work long hours, not have a lot of time for personal life, travel to random destinations. You will not always have projects that are within your desired career development path, but are more around what skills you have from previous projects and the need for people to staff projects. Compensation wise, don't go to work to ACN for the money. Their structure is not competetive until you get to manager.