Just to be clear, I think class wars for amps are silly. The OP and other readers should buy what they like the sound of without much concern for the amplifier "class" except perhaps for heat and weight issues which buyers should also consider as part of the total cost of ownership.
The idea that a class is "best" isn't what my ears tell me. There are some megabuck class-A amplifiers I can't stand, and some Class D amps I'd buy over them every time.
Class D, like Class A, suffers from legendary social memory about the technical differences which is often wrong or outdated.
Far better, IMHO, to compare Luxman's Class A integrated to the Luxman A/B units. Listen for yourself with your speakers to decide. The specs are (except for power consumption) kind of irrelevant.