We had a fleet with the PW-121/124 as well as the Garrett TPE-331-14GR/HR and the Garrett used less fuel on same sectors, was mated to an airframe that flew 40 knots faster and didn't used nearly the same amount of oil.
The engines are beefed up to those that you might have seen on an old turbo prop Commander. They are flat-rated to 1650 shp with an APR to 1946 and protected to some degree by an IEC system that also allows a monitored simple start procedure with variable ITT protections.
I really enjoyed this plane alot! I never had any real problems with the ones we flew. Sadly we did have an old Impulse one for a short while and it seemed like some of the stuff on that one got fried pretty badly. It was in the hangar a whole bunch.