As mentioned, I have a 2520 and use the Frontier GM1072R. I have very hilly property and I have to mow in 4WD all the time. I also keep the loader frame on and have three rear wheel weights per side.
While it is a little bit of a handful for the tractor to move around, I have been absolutely thrilled with the cut quality. In fact, I think the cut quality is better than the 62D MMM, mainly because the rear mower follows the contours of the land better.
I've used it for 2 1/2 seasons now with no problems. The 2520 has plenty of power for this mower, so I'm sure the 2720 could handle it.
Best of luck with your decision.