Out of all the stuff you mentioned I am the most impressed with Sansui. After owning an AU-9500 that blew me away with it's performance. Not only did it sound great it was built. The knobs and switches were tight and firm like a piece of test equipment. And, I had that the past couple years, it was built in the early 70's and still tight and right.

I sure wouldn't have left a Denon amp for $20.00. Denon had a set of monoblocks that were like $20k. I haven't heard them but in that ultra price will they compete with the likes of Krell?

Some decent gear came out of Japan but not to the quality and extent of brands like Krell, ARC, Conrad Johnson, Linn, Naim, and the like. Well.... as JM mentioned there is Esoteric so I can't make a complete blanket statement. And, there is the Marantz Reference but I'm not sure technically were that's from.