As a person who has experienced "black Monday", I feel more or less qualified to respond to this. I transferred from MUA Nevis to SMU. At MUA, we had black Mondays. The format does somewhat simulate the extended format of the USMLE, but is still not going to really prep you. What it does do is make you cram more for the exams, and you miss a lot of concepts that you would otherwise understand given more time to prep for each exam. I think it has both good and bad points, but the bad outweighs the good. Cas in point: MUA Nevis has now abandoned it, at least for the upper semester classes, according to friends I have that are still on Nevis.