Note that each of the MBBs hire just around 5 ppl each year, so for others interested in consultancy, they are left with the second-tier ones (OW, LEK, etc.), boutiques, and Big 4. Big 4 salary may start off much lower than the elite consultancies but the pay after 4 years is still much better than the typical bank officer and such, plus the prospects from there are great.

Salary scale isn't very much different from the other Big 4 lines, maybe just a little higher bonus (esp now that advisory is becoming a larger and larger revenue generator for Big 4). Work-life balance is just as crappy (but also depends on project nature).