I have been a Naim user for many years, 10 to be exact starting from NAC202/NAP200 for 7 years to currently 282/HCDR/250DR. The sound of the Luxman is very different from the Naim. The Luxman is much more neutral with a delicate and refined delivery. If comparing between the L-590AXII and 282/HCDR/250DR, the Luxman reproduces music with more sophistication, sounding more nuanced, refined and detailed than the Naim. The Naim sounds bolder and more forward in comparison with slightly better macro dynamics.
The sound of the Naim is more colored than the Luxman to me. Other users who own Luxman and Naim appear to share the same sentiment. The Luxman sound is pure, while with the Naim it appears that it’s adding something to the sound which can be desirable in some systems, not so much in other systems based on highly revealing speakers which tend to reveal all the warts.
With Naim, to get to the same level of refinement and detail, I suspect one needs to go up to NAC 252/Supercap level which will cost a lot more than the Luxman.