I've had four: 2 PRRI, one original 74' Silverface and one 64' Hand Wired PR, which was by far the best of them all. I bought all of them for the same reason, and ended up selling them all for more or less the same reason. The first one I had I replaced the speaker with a Celestion Gold as I just couldn't stand the "flab" when the volume was turned up. However, I loved the size, weight and the built in tube reverb and tremolo. Ultimately I sold it as even with the speaker swap, it still flubbed out.
These purchases were over a period early in my electric guitar playing, so I guess you cold say I was "chasing tone". After trying out other amps (Mesa Lonestar Special and a Swart AST Master Mk II), I came back to the second PRRI, for the same reason as I bought the first one: size, weight and the features. I figured this time though, I'd just leave it alone. I got rid of the Mesa due to never being happy with the ridiculous array of controls and the weight. I will give it this though, the clean on that amp, is sublime, and the reverb is fantastic. The Swart is a mid-heavy amp that in as much as it's very well made, it has a mid bite that botherer my hearing.
The same time I had the second PRRI, a friend gave me his 74 Silverface which wasn't working. I replaced all of the tubes and had the speaker re-coned as it was torn and some work done by a local amp tech. In the end, both it and the second PRRI were sold for the same reason: flabby sound. I found the bass very unstable in both of them. All three of those PR's sound great at relatively low levels. That's what the PR is known for: tone, not volume or OD.
After mucking around with a couple of other amps (another Swart and a Blues Jr.), they both got sold and I was literally amp-less for several months. It was cathartic, I have to say. Well to be fair, I have Roland Blues Cube, and that's what I used for several months (it's got it's application, and it's not worth selling).
Cue the pandemic, and I was on the prowl again. I heard about the 64' Hand Wired PR and had a chance to check one out, new, right out of the box. However, I had heard via the grape vine to look for another speaker as the Jensen was described as ice picky and shrill, something that I'd say was an issue with both of the PRRI's that I had. I decided to go with an Eminence GA10 SC64, which was designed by George Alessandro with Eminence specifically for a PR style amp. That amp pretty well sealed the deal and the speaker swap did the trick. The tone was the best of any of the amps that I had mucked around with. It's still not an amp that does OD well, at least on its own, but a pedal can easily solve that problem.
As the pandemic appeared to be not going anywhere in a hurry, and we were all virtual prisoners, I decided to alleviate my boredom with another amp purchase, something that I had often wondered about, but never tried: the Fender Custom Deluxe. There was one store in the entire greater Toronto area that had one, new, though a floor model. Supplies were running out and there was no date on the horizon when new stock would be available. As soon as I plugged in, I knew I had found another tone to fall in love over. I was, and remain mystified at the interaction between the inputs. What appears to be so simple, apparently is not, at least to this amateur picker with zero knowledge of electronics.
Placing the two of them side by side, I named them Dr. Jekyll and Mr. Hyde. The PR of course is Jekyll, and the Deluxe, is Hyde. After some time, I realized that I was playing with Hyde far more than Jekyll. The monstrous tone out of the Deluxe is something on its own. It has a fullness that is way beyond the PR. I decided that in as much as I liked just about everything the 64' hand wired had, there was no point in keeping both as I don't gig, and I don't want to have two amps in the living room, where I like to pick, so the PR was put up for sale. As the pandemic raged on and there were no 64's available anywhere, I was able to sell it for the same price I paid for it.
It's been a journey, and I totally get why the PR is an enduring amp, in spite of its limitations: tone, tone, and tone. It's a grab and go amp, and takes pedals well, at least in my limited experience. It's got two on board, tube driven effects, eliminating the need for those pedals. I have read, and I'm not sure if it's true, but it is apparently the most used amp in recording history. That says a lot. There's also a tremendous amount of history, cache, and mojo in it, which is why so many people still buy it spite of there being clones out there that might be cheaper and better made - though I can't imagine there would be something better than the 64 hand wired with the GA10 SC64. Cheaper maybe, but not "better".
I highly doubt I'll be going for a fifth, as I have found the tone I have been lusting after. The deluxe is like a less refined, simpler, older "brother" to the PR. That being said, the PR is not an amp that I would bash, and I totally get why so many people gravitate towards it. My $.02 worth.