Of all the items listed above, the Gryphon is the clear winner in my humble opinion.
A few years ago, I did an extensive A/B/C/D/ comparison using the predecessor to the Diablo, the Callisto 2200, I believe.
I compared it on THIEL 7.2's, PipeDreams 18's, Martin Logan...(13K, forget the model), so it was a test of several types of speakers. I compared the Gryphon to the Ayre/Ayre, Ayre/CJ, McIntosh amp/Preamp, Krell FPB 600/Krell preamp...just about all combintations of in store gear that 'matched up' as worthy combinations.
The Gryphon won, not only in my appraisal, but to everyone else who I polled informally.
The Gryphon to me, has the exact right blend of power/finesse, soundstage, musicality, imaging, detail, pace, rhythm...you name it. The stuff just sounds magical.
It's a shame that Fleming Rasmussen has a h.o. for America.
I think they could do very well in this market with worthy distribution and committment, something they've never had.
Go with the Gryphon, it's magic.
Good listening,
Larry