Too bad that the Yamaha A-S3000 doesn't have the classic Yamaha loudness like is on their lesser amps (like A-S701). Yamaha had the best loudness solution. That is a feature I would bass such a decision on.
Generally speaking, both Luxman and Yamaha know how to make an amp that takes the signal as produced in the recording studio and amplifies it accurately (without audible change). Anything different would be distortion, after all!
Look to adjustment via EQ controls if you want a difference in the sound, the basic amp should be essentially identical.
I know you have probably read articles talking about substantial sound differences, as if they were inherent in the amp, but any such change is negligible compared to the difference from changing speakers or the effect of the room on your sound! (or moving your head or a speaker 6"!)