There are 2 versions of these amps, the original and the II. The QS website has the manuals for each, and I believe the rectification is the difference. There is also a nice review of the original on the internet, and the consensus was that it is lacking in the nether regions, has a slightly forward midrange, and is balanced in the highs given you don't use EH power tubes (awful to my ears). I lived with the M60s (also 60W) and found that to be dead on accurate. I liked the amps, regardless; however, the guy I bought them from owns and prefers the KT88II due to its tube rectification. I would say $900 would be reasonable for a pair in very excellent shape but no more due to their age.
