At least at the grad level, the difficulty of MBA programs tended to vary enormously depending upon how good your math, computer, etc. skills were.

And, to be clear, I'm not talking about hard math. I tutored some first year students at one point and, with no exaggeration, they mostly couldn't do high school algebra or really grok a supply demand curve in microeconomics. There were a few business school memoirs written around that time and it was invariably about the struggles of someone who couldn't handle math.

Other than that, it was a fair bit of work but it wasn't really hard.