I would be very grateful if any of the bush pilots out there with experience in the Cessna 208B and/or the PC-6 Turbo Porter could give me a rough idea of the operating costs and their opinions of these aeroplanes.

Many thanks.

Can't help on costs but the two are vastly different aircraft.
The Pilatus is a pure STOL specialist. It is slow, has a very short range and is not in the same payload class as the Cessna. It will, however, operate in areas where nothing else except a helicopter can but conditions that actually require a Porter are, I think, very specific and peetty rare.
The Caravan is a big, tough cargo hauler with huge cabin volume, enormous cargo door, reasonable short field performance, handles rough strips well, has good range and respectable speed. It is also a good people carrier (up to 14 or so for the 208B) and the seats pop in and out easily. Its maintenance is as simple and as cheap as any turboprop can be. It is dead easy to fly and viceless. The one I operated did 1800hrs in a year in Africa - mixed pax/freight mainly to rough strips with no tech probs except two avionics faults which is nothing to do with the aircraft.
If you want an aircraft that can just goes on and on working regardless of the conditions it scores highly and I expect the Pilatus does too, it just does a smaller and more specialised job slower and at shorter distances.

No doubt someone more up to date than me can talk of costs.

Thanks very much!

Operating Costs for Cessna 208
PQ Avg.Fuel (GPH): 54.00Fuel Costs/Gallon:2.82Fuel Costs/Hour:158.50Oil Costs per Hour:0.61Maintenance Cost/Hour:95.63Hourly Engine Reserve:33.50Prop T/R Reserve:3.32Total Variable Costs/Hour:292.38Average Speed (MPH):170.44Cost/SM:1.67Annual Insurance:12,798.41Annual Hangar/Tiedown:6,927.24Training:9,565.67Total Fixed Costs:29,291.29Hours/Year:469.65Fixed Cost/Hour:66.13Total Variable & Fixed Costs/Year:169,341.02Total Costs/Hour:358.53Total Cost/SM:2.10

Well I earn Pesos so that sounds very cheap :)