an MBA from Yale, Princeton, University of Chicago, etc isn't worth the time?
Princeton doesn't offer an MBA.
Yale - Maybe, if you are set on financial services in NYC. Still, the MBA program's reputation trails its regional competitors. Also, Yale has one of the largest % of grads that go to work for non-profits (avg salary of $75K). With tuition at 55K/yr, I don't think those people ever see a positive return.
Chicago - I haven't looked at the numbers, but my guess is the returns are pretty good for Booth grads.