Personally I’d never go from Luxman to Pass, so I would not make that choice without listening. The idea that Pass would be universally better does not hold up to my ears.
The 509 and 507 are incredibly similar, with the main difference being slightly lower output impedance thanks to more output transistors in the 509.
If you have more challenging speakers, the 509 is the way to go.
As I've said before, in kind of the same price range I suggest Ayre, Luxman and Pass as integrateds with decidedly different sonic signatures to listen to. Among those, if you can't find a strong preference, go with the cheapest.
Also, the Loudness feature on the Luxman is really nice for late night listening. :)
Best,
E