Some HST are better than others. We have an '06 TYM 23hp Hydro and it works great for loader work. I had a '13 Massey Ferguson 1643 Hydro and hated it. It was loud and whiny with lots of power loss. No thanks.
Got rid of the 1643 and bought a MF 4707 with Powershuttle. Love it. Recently bought a new TYM 2515R with syncroshuttle. Love that tractor too. I won't go back to an HST tractor.