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. 
ggavetti
My 2 cents. McIntosh MR78 is an excellent tuner that also has that look. If you get lucky, maybe it has had the Modafferi modification already done. Pair it with a classic integrated unit. Synergy doesn't seem to be all that important since it is just a tuner.  Better yet, add the McIntosh Mi3 to hone in the tuning and add awesome visuals at the same time.
I bought a Sansui AU-7700 and love it so much I bought another Sansui of the more advanced alpha series... The sound is more refine yes, but I like the Au-7700 so much, that I listen to it mostly with speakers and headphone... There is better ? Yes, but at which price? And better for what? Where is the contemporary product that have so useful tone controls of the highest quality, a separated pre-amp function of great quality, a useful loudness button, a phono section of the highest quality adjustable , etc etc...? The answer is no contemporary amplifier had these many features...

The Sansui is so good that I dont listen to any limitation when upgrading the source, on the contrary with any upgrade of source, with any tweak to the electro-magnetic fields of the gear and room, the Sansui seems to sound better, totally detailed and organic, holographic and tube-like...

The real question is not: should i buy vintage or contemporary ?... The real question is "with a low investment", which contemporary low cost amplifier can beat a Queen of yesterday’s audiophile kingdom like a TOTL Sansui ? The answer is none ...

I can crush my Sansui if I buy for example a dreamed Berning ZOTL amplifier around 5000 bucks, but the Sansui cost me 100 bucks+150 bucks to clean the old catalytics etc... The other question is the Berning amplifier will be better but the margin of improvement will equate with 4,500 bucks more than the Sansui price... Is the Sansui so bad that I want to upgrade it? The answer is no, except if I bought a winning lottery ticket...
Vintage Speakers, TT, Reel-Reel, Tuner but use a modern integrated. I've owned a good bit even Fischer 500c and 800c the 500c all rebuilt to slightly better than new by the Fischer Doc. And even that was trounced by a $400 Chinese tube integrated.
I went through a stage of vintage late 70’s receivers. Had a few. All completely recapped.
pioneer Sx-1280
JVC JRS600
Pioneer SX-5580 (same as sx-1050 but black face and multi voltage)
Sony str-v7

they really held there value. (Except the JVC-JR S600, although one of the best sounding after the complete recap, it really didn’t have much resale value. )

mahgister is right, you can’t get features like these anywhere near the price point.  

I will I’ll say that upgrading power and better caps made each one of these something special. And a lot of fun.
I bought a Kenwood KR8010 back in the late seventies and have only had it worked on once since then in the late nineties I still use it in an old style set up and it still looks and sounds great, I have seen them listed online from time to time you might want to check into one of these receivers they would sound great with an old pair of JBL speakers.