PZL now make a version of the AN-28 with P&W PT6's, not sure of the - # but saw it flying in Indonesia.
As for the PC 6, it is a machine of note, and there is not much it cant do with the right driver, however therein lies a problem. It is not that easy to get a porter driver who knows how to fly the machine properly, and it is less forgiving than Pontius Pilot with a rookie at the controls.