audiozaz
rtfm!? - tl;dr
Here is my experience, however small it may be.
70ies: I have a KR-5200 receiver. Very well-build and super-heavy. It has had relay and potentiometer issues, so did not go into a system for too long in my house, but it has been pretty good when it worked. I'll try to get it working again this winter.
80ies: a friend of mine picked up a KA-52 (IIRC) silver-plastic-y integrated from the mid 80ies I'd guess. While cheesy looking from the exterior, the low-profile power transformer in it is quite hefty and gives the unit a heavy feel. Nice big Elna supply capacitors and discrete outputs mounted on substantial heatsinks. I serviced it and gave it a bit of a listen, seemed to do a good enough job for sure.
90ies: I use a KM-X1000 stereo power amplifier in my main system at the moment. 130WPC, brigeable to 270W mono, THX-certified. It's from the mid-90ies, where it was marketed as an amplifier for subwoofers and rears, but does a hell of a good job at stereo. Not everyone's cup of tea, as some will deduce that THX = low distortion + low noise + high damping factor = lots of negative feedback, but I like it very much. And I also like SE tube amps.
Why would I stick to a belief system that allows me access to less toys? 
az
70ies: I have a KR-5200 receiver. Very well-build and super-heavy. It has had relay and potentiometer issues, so did not go into a system for too long in my house, but it has been pretty good when it worked. I'll try to get it working again this winter.
80ies: a friend of mine picked up a KA-52 (IIRC) silver-plastic-y integrated from the mid 80ies I'd guess. While cheesy looking from the exterior, the low-profile power transformer in it is quite hefty and gives the unit a heavy feel. Nice big Elna supply capacitors and discrete outputs mounted on substantial heatsinks. I serviced it and gave it a bit of a listen, seemed to do a good enough job for sure.
90ies: I use a KM-X1000 stereo power amplifier in my main system at the moment. 130WPC, brigeable to 270W mono, THX-certified. It's from the mid-90ies, where it was marketed as an amplifier for subwoofers and rears, but does a hell of a good job at stereo. Not everyone's cup of tea, as some will deduce that THX = low distortion + low noise + high damping factor = lots of negative feedback, but I like it very much. And I also like SE tube amps.
az
Regards.