The limit on the new iMacs is 16 GB and obviously in the case of bootcamp it would all be available (unlike running Windows virtually), but your point is well taken. There are good arguments on both sides to be sure. One option is to use the Mac version but keep my old Windows version installed on a small virtual or bootcamp partition for the cases I would need the lead sheet window.

On a different point, you had indicated your missing the ear trainer that is available in the Windows version. It's an added program/expense, but you may want to look at Earmaster Pro if you haven't done so and/or are not familiar with it. I find it to be a very good and flexible program.