I mow 3.5 acres with my 2520 and 62D. I chose the 62D because of the ease of removing and attaching it. My 2520 has R4 tires, and I don't run into problems tearing up the grass unless the ground is super wet, or I have it in 4WD.
I bought the 2520 to avoid having, storing and maintaining two different pieces of equipment. My 2520 also has a 200CX FEL and a rear blade, so it does a variety of other duties.
I think the 2520 is really a great mowing machine because it's still not too big to maneuver, and the hydrostatic drive makes for quick reversing. No, it's not zero turn by any means, but it does all the things I need in one package.