The big wins here are likely the increase in thrust and ultimately cruise speed, which makes twin props more competitive with very light jets, and the decrease in noise which may make more airports accessible to the aircraft in question due to local noise limitations.

The big loss here is purchase price and maintenance price. But that's on a scale that's probably not bothering a person who can afford a brand new Beechcraft King Air or to completely refurbished a used version of the plane in the video (they quit making the Piper Navajo 30 years ago).