Yes, the Walter engines are cheap to buy and operate but very good. Due to their price, light weight and reliability, they are being installed in a number of western agricultural aircraft to replace radials, PT6's and Garretts.
No mid life HSI's, no fuel nozzel changes etc. An honest $20 per hour repair and overhaul provision - and turbine engine operating costs don't come much cheaper than that!
The LET I saw had Collins avionics. I think there was also a LET 420 produced in limited numbers with a PT6 engine, not sure what model, possibly the -27/-28 which would be a bit gutless for that size aircraft.
I did hear the LET factory was having financial problems and their larger LET demonstrator (was it a 620 - comparable to an Embraer EMB120?) had been impounded for debts.
Ball Bay, I would think most aircraft would be better than J-31's ......... a fact my "old friends" now accept. History repeated itself - TAA had similar problems with the J-31's in Western Queensland pre June 1987!
JW, can't comment on payload but I would be very surprised if the LET would pull 1,500 kg's between Sydney and Melbourne or Brisbane. The LET I had a ride in was US FAA certified, so should come onto the Australian register without too many problems. But beware of the industry and regulator mid set against Eastern European aircraft, I don't believe it is totally warranted and may originate from some western fixed and rotary wing aircraft manufacturers!