Pros
Name Recognition - Deloitte Consulting is genuinely a recognizable name among business school and other employers. Relative to working with a small company, I think that bigger companies offer employees more choice as to where they will go after they leave.
Cons
Culture is very draconian and hierarchical. There were many times when rank was invoked out of nowhere to prove a point, rather that using data to prove a point. Most projects have literally nothing to do with what most would consider management consulting. It is high-price temping at best. There is no support for new people. Do not count on superiors to lead you through. Very sink-or-swim environment. My best advice is to keep your head down, don't drink too much at their constant, and constantly awkward, office parties, and grit your teeth for two years.