Accuphase vs Luxman

All depends what you like to listen to. Luxman SS is a low distortion neutral ish sound veering on technical but not clinical. Wouldn’t call it musical flavored. 
Accuphase has a sound to it just as distinctly as mcintosh does. You love it or you hate it. Sounds wonderful with acoustic and classical. As others said, tube amps. But again not all sound the same. If you listen to rock I would recommend LTA. If you listen to older recordings and want it to sound like an amazingly good vinyl system, LEBEN.  I really like leben and to be honest it sounds like mcintosh but better.   Really don’t recommend mcintosh tubes. Sound like solid state overly saturated but fuzzy. Classical and realistic sounding then luxman tubes. 
neutral but still pretty and able to rock, close to solid state but still obvious tubes, rogue audio. 

Also the luxman tubes sound more like Accuphase made them than luxman solid state. But they are extremely lacking in bass. Really really need sensitive woofer or subs.  LTA is more like a tube version of luxman solidstatr 

Not sure what you mean:

the luxman tubes sound more like Accuphase made them than luxman solid state

Accuphase's historical and current product lines, as detailed on their official website and in historical records, are based on solid-state technology.

I have the C900/M900 mono setup; have evaluated the new models but just can’t justify the change. At least yet!!! When I decided to move from Mc, Accuphase was one of the brands I auditioned. Great quality and sound just found it to be slightly more analytical and less musical than Luxman with the same speaker setup. For me Luxman was better across a broader range of genres which is important for my listening. Someone commented that they thought Luxman lacked midrange which you only have to look at the measurements to know is not true. Maybe with poor quality speakers, but that could be true for any gear! Bottom line, unless you just want to try something new, they are close enough that I probably would not make the move without auditioning the Luxman.
 

I would agree with the comments that either might be overkill for the current Klipsch’s but this argument could probably be made to almost everyone on this forum. My wife has constant eyeroll! Certainly, gives you the headroom for future speaker moves if desired.

As you asked. Accuphase fantastic. I would seriously think about low powered tubes. Maybe 300B Amps. But why not some three way speakers.? Say Sonus Fabetd. There’s more to be had than from the LaScalas. My Khons are the weakest link in my room.