As much as some MBB consultants would love to argue otherwise, there is no real difference in personality between a McK/Bain/BCG consultant and an ATK/Deloitte/Roland Berger/...
Truth is, nearly all of us apply to both top-tier and second-tier companies. You might argue that on average an MBB consultant may be better than the others, but that's a very rough approximation and I might even disagree. But when it comes to personality, we are all the same kind of type-A jerks :)
Cheers,
Guennael -
ex-BCG