I have only extensively used rocker pedals, but I can't see my self on a two pedal setup for 2 reasons. Half of my snow plowing is done facing backward, and while I suppose it is possible to press the reverse pedal forward while facing backward, I find it better with the treadle, as I can turn around and my foot is right on the reverse side of the rocker. Also, I have big feet, and often where big boots. I think I would constantly find myself hitting the wrong pedal or both, because my boot hadn't cleared one or the other. No such issue with the treadle.
Kioti calls the CK27 the CK25 sometimes, same tractor. The CK20 is no longer made, replaced by the CS2410, and the CK2510. The Tier IV CK series will be called the CKXX10, but will still be the same tractor.