Personally,
I have moved on beyond Power Belts. I started muzzle loading 3 years ago because the place where I hunt is limited to shotgun and muzzle loading. The first two deer I killed with power belts that year showed them (to me) to be too soft and have a tendancy to break apart.

I started using Shockwaves last year and never looked back. In the past two years, my kids and I have harvested 14 deer. Three by bow, three by 20 gauge shotgun with sabots (before I modified a muzzle loader for them) and the rest by my Encore. I do not hunt with a shotgun because I just don't think it can out perform my Encore (other than followup shots, which I haven't needed). Everything shot w/ my Encore has been w/ shockwaves, my kids use the 300 grain Hornady XTP in their gun because they don't shoot a magnum load and I am not sure they would get good expansion w/ the shockwave.

I described, with pictures, our most recent experience with PBs, another blowup.
Just this week, a fellow I work with (a very dependable fellow and very competant deer hunter and shooter) shot a 100 lb doe with a PB. He said when he shot it, the doe fell, moved forward on her back legs, got up and ran off. A hunter several hundred yards away fiinished her off. When he saw the doe, there was a double fisted size hole in her shoulder, some serious jellyfied front quarter meet and cracked bones, but NONE of the lead or copper made it into the body cavity. It was like it hit the shoulder and just exploded. Thankfully another hunter had the opportunity to finish it off.

All that said, I do keep some PBs around. I keep one 295 grain PB with 2 50 grain pellets of 777 and two primers in my jacket. This is for fast reloads after the first shot. I don't swab or clean, just plop the two pellets in and then the PB and shove it home. (I could never do that w/ 110 grains of loose 777 and a shockwave) Because they load so easy and I don't need a special tip on my rod, I keep them for that purpose. Seems to me that for finishing shots they are probably ok. Knock on wood, haven't had to use the load yet.

I know some folks have great luck with them. But I have personally killed three deer with them and won't use them as a primary load ever again.
R
Hank