Well, It's NOT a debate unless someone takes the alternate perspective. Other than around FARMALL in the late 70's & early 80's was I ever around a Hydro CC. They used them all over FARMALL to pull trash hoppers, lawn maintenance, remove snow from driveways, etc. I got to know the head of the maintenance garage really well during the BIG Strike of '79 & '80 and We got to talking Cubbies. When they got their first hydro their up-time went WAY up as opposed to the gear-drives because of the lack of clutch/brake problems. I got My first hydro in about '90, a basket-case 129 that had been over THOUSANDS of acres of lawn. Other than a couple hydro oil changes & filters and replacing that stupid cork gasket once I had NO problems with it.
That said, I use My gear-drives MORE than My hydros, which is now just a 982 w/50C deck. It mows faster than the 70 (which doesn't "Mow" at all!) and the 72 w/38" deck. But I don't just mow. I haul trash, tree trimmings, been to a couple plowdays, push snow with the belly-mounted grader blade, I've even run the QA-36 blower with the 72 a couple winters in the last few years. Snow gets deeper than 3-4 inches the FARMALL's come out. With the K181 in the 72 I could only handle 3" deep snow well, with the K241 about 5-6, with the K321 in there now I don't think the blower would handle the HP and I'd wrap the auger up in a little ball!
A K301 should be able to run a QA-36 without a creeper fairly well. Get in deep snow just take half a swath.
And keep Your speed up. Without pulling something REALLY heavy those little 4-1/2" single plate dry clutches can take a LOT of abuse.
If Your only going to have ONE Cubbie I really don't think it makes a difference whether You have a G/D or Hydro. I can actually trim around trees/bushes as fast with the G/D as I can the hydro. I find I sometimes run out of hands with the Hydro when I can ease into a place using My left foot. If your going to have TWO Cubbies, then get one of each.
At the last PD where I had My 982 I checked the hydro temps of My 982, Wyatt's 169, and I think Bryan had His 1650 or 1450. Those hydros DO get warm when pulling hard, 225-250 Deg. F., almost too hot to touch! My G/D was about 55-60 Deg. F., just about ambient temp.