Currently flying the N24, its not a STO machine, but does the L pretty good!
We've got the new flap Mod which allows us to use full flap again, instead of none or 10 degrees.
We have had no problems in operating them over the last 24 years, as long as they are maintained and operated as the manufacturer specified. We had one aircraft that performed a scheduled run on behalf of Air NZ, and had better reliability than the Metro/Saab that also performed the run.
Certainly having the enhanced B17 on board greatly improves the hot & high performance, with an OAT close to 30 degrees C at 2500' AMSL, we can easily get full rated power out the engines, the other without the enhanced turbines seems to run out of puff with those conditions. Plus the added bonus is the fuel consumption with two engines is less than the C208B. Maintenance is also cheaper than the C208B too.
The NG N24 which Gippsland Aero are developing would be a great machine!