If you have a diesel 3/4 or 1 ton truck and a 10k or bigger trailer you're fine with the M6060 or M7060. If you have a half ton or gas 3/4 with a 10k or 7k trailer the MX5200 will be all that truck-trailer combo wants.

According to specs provided by Kubota the HST uses up 1.5 hp (vs a DT) on a tractor that is 54.7 gross hp at the engine.

The transmission would make my decision. If you want an HST get the MX5200. If you want a shuttle shift, get the M6060-7060. The MX non HST is NOT a shuttle shift and the M tractor only has one style of transmission available. No wrong choice here.