Top vintage receivers vs. modern high-end equipment

I am considering pairing an old amplification system to my JBL Paragon -- the idea of getting an all vintage system is very attractive to me. Among other things, I am looking into classics such as the Pioneer 1980 receiver or the Marantz 2600. Does anyone have direct experience in comparing this kind of equipment (very high-end but 40 years ago) to current high-end equipment, imagine an integrated Pass Lab amplifier? How do they stack up? Thank you.