The Powerbelts, originally developed in 1985 (Del Ramsey), are fundamentally conicals. I like them-- they are easy loading and fun to shoot.
(Opinion) The .50 caliber, lighter weight versions have a fundamental flaw-- they have wide and deep hollow points. The problems you hear of Powerbelts are primarily with the 245 gr. / 295 gr. versions, far less with the 348, and I've never heard of any less than excellent results with the 405 gr. or 444 Flat Nose examples.
There is a good reason why. The hollow point is the same size and depth, whether 245 / 295 / 348 / 405. Still soft lead, a hot 245 gr. PB can fragment badly. You'll most often hear of this when a "3 pellet" load takes a deer at short range. The bullet can blow itself to small pieces.
The Aerotip exists to retard expansion, and the polymer material was recently hardened to improve upon that. Not much of an issue with the 405, as the nose can blow off when hitting bone-- and you still have a lot of mass left to drive on through. With a 245 gr.-- no similar possibility.
So, the trend (according to their makers, Big Bore Express) is that the 295 Aerotips at moderate velocities do a competent job on thin-skinned game, with the 348 HP fine for deer, but 348 Aerotips or 405 HP's a far better choice for elk or similar. The heavier bullets aren't pushed that fast, anyway, even with three-pellet charges. 150 grains of pellets pushing 405 gr. version gets you in the 1680 fps range.