Hydro's are better suited to mowing lawns - its easier to use a manual offroad, have more control and can take more of a beating . Hydros can overheat if the fan breaks, or if theyre run hard - theyre also specifically set for certain gear ranges - no modding one.
I have a spicer 4 speed & I like it. Easy to work on & easy to change gearing. I use mine for moshing in the snow and going fast. Just change a pulley & belt and go. I don't beat it or jump it. I've ran it hard and the only prob. I had was the wooddriff key . I know both kinds of tranaxles don't like pulling lots of wieght all the time. It kills them.