Hey Ken,
Have you had a chance to A/B the RH450 with your Puma yet? I have the TC 210/212 stack and my Puma sounds great through the TC speakers, but I'm curious about the RH450. I had the MB LMII for a little while and while I thought it sounded pretty good I wasn't blown away with it. I preferred the sound of my Puma with the Epi 410UL over the LMII. I was just wondering how you would compare the RH450 with the Puma.
I have a little bit of a review up in some thread, but can't remember which one.
I did a pretty good a/b/c/d of these heads with a few basses and my AE410 when the RH450 arrived.
I found the RH450 and LMII to be more similar than different (I could get the LMII to sound quite a bit like the RH450 by engaging the VLE, although of course the LMII will not 'grind' like the RH450 will with the tube emulation control). The RH450 was a bit more chewy and low mid punchy, and didn't have that nice upper treble extension like the LMII (hence the VLE 'equating' the two a bit), but has much more punch and force (that 'kick you in the chest' sort of thing).
Basically, the Puma is much cleaner, much purer, much deeper way down low, more hi fi up top, and not nearly as punchy or loud in an absolute sense as the RH450. I believe the Puma500 (that's the only one I'm familiar with) is probably the best sounding head available... IF you are looking for pure and transparent, with a nice fat, warm low end, along with a very glassy, pure, airy, hi fi top end. And, the low mid control is wonderful with the Epi cabs, adding a bit of punch and burp. The RH450 is more of a mid punchy beast, and will get quite a bit louder, at the expense of that 'pure fidelity' of the Puma.
Hope that helps a bit. They sound quite different!