Anish,
Firstly, even if you consider the top-consulting firms, there are very relevant differences from country to county and even from unit to unit inside the organization.
Additionaly, getting an MBA is becoming a very ordinary step on consultants' carrers, so the education market noticed that demand on advance and nowadays you can taste virtualy any "flavor" for an MBA course.
In terms of boosting a carrer, I consider an MBA specialy usefull if you have formal education in technical or scientific areas of knowledge or if you intend to become a strategy consultant. In the first case, you could start working and then take your part-time MBA according to the education policies of your employeer. In the second, it would be better to get a very respectable MBA before entering the firm.
Despites of the MBA, I consider that a good project management course (such as PMI education) is a decisive investment for anyone who intends to get in the consultancy field. If I were not immediately interested in strategy consultancy, I would take such a trainning first and then invest one or two years working hard for a consultancy firm, then I would start an MBA and, probably in 5 years it would be possible to have some fluency in management-consultancy.
