What's Your Take on This ?

In 1985, or thereabout, I owned a pair of Audioplan Kontra Punkt mini monitors ($500) that I heard paired with Threshold amplification. I could not afford Threshold then and from great reviews got the Adcom 535. Well, the 535 could not produce the stunning presence and focus that I heard from Threshold. So, a night and day difference between the two.
Kenny

While a product might have the same name on the front as did another product from years ago, the question is rather whether the two products share any design DNA or even the same company principals (and principles, for that matter).

I owned a few 535s (formerly my main amp years ago with the Adcom tuner/preamp, also used one as a recording studio amp and their great as a utilitarian extra speaker amp) and after moving on and selling most of them over the years I was down to a 535II (more standard binding posts) and a clean 5300. I think the 5300 is under appreciated and I wound up keeping it over my last 535 as it simply sounded better. Now it’s a backup/SS reference amp that drives outdoor speakers and is simply a killer amp. Note that clean versions are still around and are very inexpensive on the used market. Highly recommended. I also owned an Electron Kinergetics Eagle that developed  issues and I traded it for an Acurus A250 that also had issues, although covered by warranty. That led to another couple of 535s, including the MKII, and a Forte Model "55" which was a great amp. After that it's all tubes (the 5300 being the exception).

Really? I had an original 535 and never considered it worth beans. I've had hundreds of basic amps, most of which I've made but plenty of commercial designs and I have to say that the Adcom 535 was utterly undistinguished.
The original preamps that they made, the GFP1 and 1a were both great for the time and the price. The 565 preamp was stellar for the time. The GFA-535? No so much.

I can't find it right now; but I recall reading an article on Human speakers and their designer/builder/owner Huw Powell. The piece mentioned that Mr. Powell has one Adcom system in his office and one in his shop. I wish I could remember the models; because I consider this to be very high praise.