I have tillers on several garden tracotors and most work well.Hands down a hydro transmission is the best to run a tiller with.To give you some idea on whats around here's a list of garden tractors I have tillers mounted on.
Craftsman FF 18 Craftsman FF 24
Ariens GT 18
Massey Ferguson 1855
Simplicity Hydro 18
Personally the MF 1855 with a 3pt shaft drive 4ft wide 2000 RPM tiler is my favorite as its a hydro with foot control and heavy enough to hold the tiller easily.