The Fletcher was designed as a topdressing aircraft for NZ. In my humble opinion the best machine (With it's derivatives) for the job. John Thorpe also had a big hand in the Piper series aircraft, full flying tailplane and similar design to the Flitch. Turbines have made a big difference to AG work. But as usual if you give an AG aircraft more power the hopper size goes up till the advantage gained is negated. The Dromader is an example, 2500 litre hopper for bulky products like seed and some fert. They stuck a turbine on it and blew the hopper out to over 3000 litres then filled it with retardant for fire work. Not only that with the radial you were working at around 100 kts, the VNE is (from foggy memory) 125 kts. With the turbine they were cruising at 145+ kts and spraying cotton at 130 kts, little wonder the wings fell off.
If I had a choice between turbine and radial (if earning capability didn't come into it) I would choose a radial/piston. Every piston has quirks, an individual. Turbines seem to be bland, lots of power but bland. Switch them on and off. Pratt 985 or Lyc 720's all had personality, both at idle stirred the soul