The process took 6 weeks. I interviewed at FTI Consulting (New York, NY) in Dec 2011
Interview
There were two rounds. The first round was relatively easy, just going over your resume and various behavioral questions for half an hour. The final round consisted of 3 1:1 interviews, each questioning you on various skills and thinking methodologies, etc. as well as a presentation, which was probably also a test. The final round was a long day for sure. FTI was also stupidly slow with the time it took them to notify you of admittance to the next round and then of the offer.