Vantaggi
I've worked twice for Accenture, once in Consulting and once in one of the BPOs. Accenture Consulting is a great place to work. Challenging, interesting work, great comraderie, high rewards. You get to work with great people, and the work changes constantly.
Svantaggi
For consulting, travel and work/life balance are very difficult. It can also be difficult to control the direction of your career, because you're often staffed where you're needed. It can be hard to build up expertise in a particular industry or technology. The BPOs are also very tough - they're the ugly stepchildren of Accenture. Accenture is putting a big push into BPO, but they haven't figured out how to integrate it well with the culture. It's viewed as a secondary career path, and people are not treated as well as in Consulting.