Maguiar,
I did demo the Gryphon Diablo 300 with the 11As. Thought it was great, though certain songs came across a bit bright, and at times slightly harsh. Generally it had a great balance of warmth and clarity, but was surprised at the brightness that snuck in every now and then. It was enough where I could see potential fatigue setting in. I think it was paired to a higher end DCS DAC, didn't check to see which model. If I was to consider the Diablo again, I would want to try to do a more thorough demo.
I got a great deal on the Luxman 509X so figured I might as well give it a chance given it was pretty much half the cost the Diablo. So far I like it, but working on trying balance the system a bit more since it is a very transparent amp. Just picked up a new interconnect to try out. The 509X is the first amp I have owned which let me really hear the obvious differences between my copper vs. silver interconnects.
On the PS Audio DAC Caphill mentioned, one cool factoid is that their DACs are firmware upgradeable. You get a new and improved DAC with each free software update. It's on my list of DACS to demo with my system down the road, though I am really fascinated with LampizatOr DACs out of Poland.