@michobr59 Sorry I'm a little late to the party but I thought I'd share my experience with you. About 3-4 years ago, I started replacing my components and went out and auditioned a whole bunch of integrated amps and speakers. I finally settled on Hegel and Luxman and almost bought the Hegel 390. It is an excellent amp and does most things right. I was especially impressed with how it took absolute control of the woofers of my speakers (at the time I had Sonus Faber Olympica II). The sound was refined, powerful, and had great imaging. I almost bought one until I had an opportunity to listen to Luxman 509 and 590AXII. The 590AXII was the one that eventually won my heart. It had that special something that spoke to me at an emotional level in a way the Hegel did not. As someone mentioned above, it is very refined, balanced and neutral but with a hint of sweetness without ever going overboard. The bass, although not as big as the Hegel, is more taut and nuanced. The upper frequencies extend in a way that it would remind you of tubes. In short, as good as the Hegel is, in my opinion, the Luxman brings something more to the party. I disagree with folks who say that you're basically paying a premium for the looks. I think even if the build quality and finesse was not there, Luxman would still stand on its own based on sound quality alone.
I also disagree with other posters who think the Luxman is more on the warm side. I found both 509 and 590 to be neutral with just a hint of warmth. It is truly an outstanding integrated amp that can be an endgame component for many.
Having said that, I found another integrated amp -- Audio Hungary Qualiton a50i, that checked more boxes for me. It is as good as the 590AXII (except in the bass department) but brings that holographic, 3D, and lush soundscape that only tubes can provide. I could have easily lived with the Luxman but the Qualiton a50i with it's 50 watts of pure class A was a better fit for me. Good luck!