"Define "not bad". What's involved?"
You have to remove the top link and both draft arms. Then, remove all the MMM attaching hardware and the MMM. This isn't as bad as it sounds because it's all just lynch pins that hold this stuff on.
On the units with hydraulic mower lift, I think you have to remove a part of that system (which I don't have).
Then, you just back over the sub-frame and use the hydraulics to raise it into position. Put in the pins and away you go.
I have both, a rear finish mower and a MMM and there's not that much more to removing the MMM. You have to remove the three-point arms and top link in either case.
Again, I wouldn't want to be doing it multiple times a day, but for just doing it every once in awhile, it's not bad.
Would I rather be able to leave the sub-frame on the tractor with the three-point and/or MMM?
Absolutely.