Pros
If you like to travel, this is the place for you. Points, perks, frequent flyer miles, nice dinners, a certain amount of prestige. Getting thrown into something you know nothing about and being forced to learn on the fly (stretch roles). Good industry contacts, good alumni network, good exposure to industry.
Cons
You are expected to give give give. There is no 'official' tuition reimbursement program. Accenture doesnt seem to care much about education other than the lame to average learning offerings. It is very very difficult to get people to think/act/contribute outside their silos. Pay is below average for the level of expected performance. If you get stuck in certain areas or with certain groups, your opportunities to learn and grow will be hobbled compared to those who got MCIM.