OP,
Just to point to the reality that your own values and system are the most important aspects in choosing an amp. I completely disagree with @mtdining on every point he makes. This does not mean he is wrong for him. I have 50 years of experience in pursuing high end. I have owned Pass amps for over thirty years and spent a lot of time auditioning Luxman, Boulder, and Spectral. My conclusion is exactly the opposite. Pass exceeds in bass extension, and particularly rhythm and pace… making his amps far more compelling.
This is why you must audition amps in your own system. I am not doubting @mtdining has not experienced what he advocates… just that our values and systems are different.