I've had the E650 and 509X. They are pretty different. Luxman has a sharper, crisp, and clean sound without being harsh or in your face. Accuphase is smooth and warmer, but with a vibrant and saturated tone. If Luxman, I would be looking at L-590AX II or L-595ASE unless you want to buy new. No way I would pay $12k for the Accuphase, but some people just love the Accuphase sound and you could be one of them. I bought a Japanese unit set to 100V for around $8k, and easily set it to 120V by moving a connector.
If you like Harbeth, Pass may be the ticket. I only have experience with XA25, INT25, XA30.5, and older Aleph models, but in general Pass has the most tube-like sound to my ears, and the most palpable imaging of the 3 brands. It gives the most "performers in the room" feeling IMO. It could be too much of a good thing if there's a particular balance you're trying to strike, but you never know until you try. Pass also runs the hottest, if that's a factor.