The 6.2L is a definite improvement in all regards. The only thing with the 6.2L I have seen were a few random broken valve springs which is a fairly simple repair. And I only mean a FEW as in I don't see it as a major pattern failure as of yet. I also feel that the 5.8L was a dog and any time I drove one I felt that the engine just laid down when putting the throttle to the floor. In comparison, the 6.2L seems to wake up at around 2500 RPM and gets the truck moving. I am a diesel specialist so that is mostly what I get to drive with regard to the vehicles I road test so any gas powered truck feels under powered except the 6.2L.