I went from a JP80 to a JP200. Tube matching wasn't as much of a problem as I had thought, as the separate volume controls could compensate for any lowered output, in practice. Tube cost, of course, was another story, just due to the sheer numbers involved. I found the JP200 just had an extra ease in the most dynamic recordings compared to the JP80, and imaging and soundstaging were substantially better as well. One caveat--my JP200 was one of the few made that used EF86 tubes rather than 12AX7s and AU7s, which definitely gave a cleaner sound at lower volumes. Another thing to keep in mind was that after the preamp my system at the time had separate active crossovers and amplifiers for each channel, so the benefits of one box for each channel were probably magnified in my system setup
Toward the end of my time with the JP200 I added a separate phono stage (first a Lamm LP2 Deluxe and then a prototype of the Merrill Audio Jens phono stage). I preferred this arrangement to either of the Jadis phono stages, in large part due to the fact that, no matter how good the tubes in either of the Jadis phono stages were, they inevitably got noisy very quickly (and also wore out quickly too). The Lamm and especially the Jens prototype (the latter of which is solid state) were much quieter and more dynamic and revealing.
So I'm kind of mixed here as far as which I'd advise. I'd say that in my system having the separate power supplies for each channel made the bigger difference in terms of dynamics and channel separation; having the separate phono stage made a big difference in terms of noise, but that is something that probably would not be as big a difference using the Jadis phono stage as opposed to the ones I used. I do think the phono stage's separate power supply also added additional dynamic headroom that I didn't get from the phono stage in the JP200, though how much of that is attributable to the different brands is something I couldn't answer. If I had to choose one way or the other, I'd go with the JP200 over a JPS2/JPS3 combo (and I'd go with that combo over the JP80 by itself).
Not sure how much this helps; some others will probably chime in here as well.
Toward the end of my time with the JP200 I added a separate phono stage (first a Lamm LP2 Deluxe and then a prototype of the Merrill Audio Jens phono stage). I preferred this arrangement to either of the Jadis phono stages, in large part due to the fact that, no matter how good the tubes in either of the Jadis phono stages were, they inevitably got noisy very quickly (and also wore out quickly too). The Lamm and especially the Jens prototype (the latter of which is solid state) were much quieter and more dynamic and revealing.
So I'm kind of mixed here as far as which I'd advise. I'd say that in my system having the separate power supplies for each channel made the bigger difference in terms of dynamics and channel separation; having the separate phono stage made a big difference in terms of noise, but that is something that probably would not be as big a difference using the Jadis phono stage as opposed to the ones I used. I do think the phono stage's separate power supply also added additional dynamic headroom that I didn't get from the phono stage in the JP200, though how much of that is attributable to the different brands is something I couldn't answer. If I had to choose one way or the other, I'd go with the JP200 over a JPS2/JPS3 combo (and I'd go with that combo over the JP80 by itself).
Not sure how much this helps; some others will probably chime in here as well.