labsrus,
Hard to say if the 2720 will be a short-lived model or not.
As mentioned, I have a 2520 with loader, 60 inch rotary cutter and 72 inch rear finish mower to handle 6 acres of fairly rough and very hilly ground. I chose the 2520 for the smaller size and maneuverability over larger machines.
Also, the bigger machines look, and from some reports, are, a little more "tippy" on the hills. I will say that I have found the 2520 to be rock solid on 20 degree slopes.
The biggest problem I have with this machine is, like most tractors, it's hard to put the power to the ground because there isn't enough weight. As mentioned, I have three wheel weights per tire on it and did not choose to load the tires due to issues mentioned in other threads on the topic.
That being said, if one did not have a problem with loading tires, I think the extra weight would be a BIG help for this machine and most who have loaded tires on one seem to agree with this.
As for the two-range tranny, for my use, the high range is just too fast (rough ground, hills) and is only usable for transport. There also isn't enough power to operate in high range on hills, particularly if your're working the machine.
The higher HP on the 2720 might help this or not, I haven't tried one. However, as mentioned, for me, the high range is just too fast, even if I had the power for it.
I have not had any problems, power-wise, running either the 60 inch RC or the 72 inch RFM. However, more power never hurts and if I was buying one now, I'd go for the 2720 just to have the extra HP.
For what it's worth, and for my purposes, I just wish they had geared the high range lower, like about halfway into the upper end of the low range. To me, that would be perfect for giving faster movement for using the loader and mowing, and I don't need to go 20 mph with a tractor anyway.
Best of luck in your decision, I think you will be happy with your choice. I am entering my third summer of service with the 2520 with no problems.