Luxman 509x VS Luxman 509Z

Hello to all Luxman owners,

I currently own Luxman 590II and Luxman 509X.  I've never heard the new 509Z and had a purchase set up but unfortunately or fortunately the sale did not work out with seller.  All that to say I'm now back on the Merry Go Round curious to any owners thoughts as to improvements they can share between the aforementioned units. Very pleased with my current set up however curiosity and impulse are making me long for making the change. Much appreciate any thoughts one can share as to their experience with said units.

Cheers!