I think most of the bad rap that PBs have gotten is due to people shoving them long with the max charge in pellets or powder. The "magnum" labeled guns and pellets for many newer, less experienced shooters gives them an out to taking the easy street and maxing out the charges just because they can, then when a shot is taken at a little closer range the bullets gernade before reasonable penetration has occurred. In reality that can happen with any of the lead cored, jacketed pistol bullets commonly used in muzzies [experience speaking here] when shot with a maximum load. I think about 99% of the power belt issues would go away if the "Magnum" were dropped from advertising and printing on gun barrels and the pellets went away so people would have to learn to tailor loads to the gun.
I've never, ever had an accuracy issue with a power belt bullet, but the cost is what sunk that ship for me. I never took a deer with a power belt but did hunt one season years ago with them.