I’m with you on the Luxman/Harbeth thing. I never really cared for it. Perhaps too much warmth? Almost too polite in terms of presentation.
I bought the Luxman L-590AXII last year and i agree with this. I own the Harbeth SHL5+ and find the Luxman/Harbeth match to be too polite and warm for my taste. I find the Naim to be a better match to the Harbeth.
The Luxman L-590AXII is a wonderful amp. It's currently matched with Marten Duke 2 and the sound quality is excellent. I didn't manage to compare the Accuphase E650 with the Luxman though but based on looks the Luxman is far ahead in my book. I don't quite dig the gold finish of the Accuphase.