You have considered the same limitations I have noticed. The 25 pto hp is probably marginal IMHO, but in reality for 95% of my tasks it should be OK. My ideal would be about 30 pto hp. Hydraulic motor ptos operate differently than true direct drive pto. I have a pto adapter for my skid steer that I use ocassionally with 6' bushhog. SS has about 20 gpm vs the 27.9 of the 5610. Hydraulic ptos just seem to lose their power and can go gradually to a complete stop with little effect on the SS. Also with tractors, as the rpm decreases from pto speed, the engine actually delvelops higher hp and torque for the first 300-400 rpm drop . Hydraulic motors get their peak hp at max flow and psi, then it is all downhill. The higher flow of the 5610 should give me more power to the pto than the SS. The SS does ok but can't run the mower well in thick grass or brush like a pto driven unit.
With the 5610, I will probably tweak the hydraulics to 3300 psi from normal setting of 3000. With the higher pressure, I should get around 27.5 pto hp.
From what I have seen and been told, the suspension is exactly the same.
The lift capacity also could be a little better. Closer to 2000 lbs would be better. My guess, is they kept it lower because the weight in the dump box was carried over the tires, and the weight now is carried farther behind the tires. From my observations of the 3 pt lift arms, I will probably drill another set of holes a few inches further back in the arms. Some of my ag tractors have 2 holes in the arm to get max lift. I don't think the change in the holes will have any other sigificant effect on the geometry.