yyzsantabarbra,
I better not listen to that combo yet. If I do I'll want to buy it. I did ask about the 900u when I was looking at the 509x, and was told that is a whole other animal but was just replaced by the 10X. The 509x uses the 700u amp and the 700u preamp. It's an amazing piece at an even better price. The Krell is a pretty good value as well.
The Luxman, Krell, and Gryphon were are all very holographic. Each had a slightly different presentation. The Krell was slightly more forward than the Luxman and the Gryphon, depending on your taste you may like the Krell better. It's really hard to say how "3D" the Accuphase, Boulder, and McIntosh group were compared to the other group as different showroom, sources, speakers. All the amps were good in that regard except the Esoteric, I don't know what was going on with that.