depending on hauling frequency, load weight, etc., answer could range from from either to neither. Also, hills and inclines can play an interesting part in such a scenario where the weight being pulled becomes more than the weight pulling. IMHO, ain't much difference between the two trannies.

Looking at specs online, both transaxles look to be rated pretty close to each other. The TT lists slightly greater capacity than the HG, but the HG has a larger pump (10cc vs 7cc). Is the HG serviceable? If not, I'd probably go with the TT, but replace fluid with 5w50 synthetic first (can be hard to find, my local auto parts store found some in the back that wasn't on the shelves).

If you are going to use it for towing only, and no mowing, I'd suggest removing the mower deck and find the smallest diameter wheels/tires you can fit on the axle. That will have the effect of increasing the working capacity of the transaxle, like putting lower gears in the rear axle of your truck. If you look at the mfr. specs on the websites, you will see that their ratings are based on tire diameters. However, if you plan to mow, than stick with the factory wheels/tires, otherwise your mower decl will be difficult/impossible to level.

My bet is on the Hydro gear being more durable.