Several years ago my college
theatre and my church got, at about the same time, a super good deal on some off brand batteries. One was labeled "Fred's Super Batteries", and I forget the other, and I don't remember which is which. At college we were about to put up a musical, so we used the Fred's (or whatever the other one was) batteries for a rehearsal. One rehearsal, fresh from the cardboard tray they came on, and every blessed one of them was completely dead by
intermission. We had similar luck with the ones at the church.
A couple of years ago I was going with the band to a gig, probably a church gig, and needed a 9V battery for one of the wireless thingies. Picked up a Danelectro-badged battery for too much money at the Guitar Center (they got things like strings and picks). "Vintage formulation" and "better tone" were the selling points on this battery's packaging, which was a huge red flag. Yep, dead in a half hour.
I've heard for some time that the Copper Tops and the Procells are the same inside; same for regular Energizer and Industrials. I trust them all about equally.
I don't use rechargeables for several reasons. Everything I use them in (and it's three radio kits at the church, one battery change a week) uses 9V batteries, and until only recently we weren't able to manufacture a rechargeable battery in that package that had enough
terminal voltage. I've heard the bleeding-edge designs can. That's
strike one. Two, even for 1.5V cells they're relatively new (10 years) to the market. The last one is trust.
I don't trust the technology yet, even for the 1.5V cells, not enough to rely on it. Other guys do trust it and have several years of cost savings and reliable service to back it up. More than the technology, I don't trust me, because you have to put the batteries on the charger and keep up with hot and dead batteries. I trust a Procell. It comes directly out of the box, only then does the cap come off (and the cap goes straight into the trashcan), and directly into the device the battery goes. I know beyond a shadow of a doubt that I have a hot fresh battery in there that I can trust for X hours of continued service.
I did have an interesting encounter with Energizer Industrials the other month. I pulled some, with the caps on them, from a box in our
workbox at the shop. Just for grins (I never do this) I put a voltmeter on one just before I was going to put it in a transmitter. Less than 7 volts. Two others, caps still on,
terminal voltages way less than 8; I think one was 5
point something. Uber dead. That's either attributable to shelf life (no idea how old these were) or to prior use (and the last user, many months ago, put the caps back on heavily-used batteries). While I don't blame that on Energizer, since they probably were just used and recapped, I can say I haven't had such a failure with a Procell.
Batteries are cheap insurance. At the end of the day, it all comes down to which battery you trust.