I can only speak to the CAT and the Supratek Cortese, as I have owned these and a set of Pks 57 Quads. The Cat worked with everything, MM and MC, etc and SS by Symphonic Line and Levinson 331, tubes by Jadis, Audio Valve Callenger with cryoed el-34s, Art Audio Jota.
The Cortese I heard and fell in love with was owned by the guy from whom I bought Wayne's Quads. He used Transition Tube amps and and Reference 3as (while waiting for a triple stack from Wayne!) After that, I looked for one for over 6 months and found one said to be "the best sounding one", that Mick's partner ever heard. It was liquid and smooth, (or was it slow, thick, lush, creamy), but out of my system in 3 DAYS! I've never had a unit move in and out so fast.
Go ahead guys, tell me all about my tin ears. I've been in high end for over 20 years and even sold gear for a while, so insults will be taken good naturedly...I trust my ears. I'm sure you trust yours.
I know those who have Suprateks love them, but I didn't like the Cortese nearly as much as the CAT (any of them) and my Emotive Audio Sira. I have heard and think that the lesser priced Suprateks have a similar family sound (so if you like it, go for it). I just didn't like the Cortese IN MY SYSTEM, even though I thought it might compliment or "slow down" my (very fast)VDH Black Beauty.
(I'd used Benz, Grado, naked Blue Points, Dynavector 17D with the CAT)
Older CATs are extremely inexpensive for what you get and Kent's service is fabulous.(I only needed one repair on one of the units in 5 years of ownership). I'm sure Suprateks must be great, I've heard one, but I sure didn't like the one I had in my system with VPI HRX, VDH, and Audio Valve Challengers/ Art Audio Jota with 300 B XLRS and Waynes Quads. CATs just seem more flexible/adaptable, but the Supratek IN MY FRIEND'S SYSTEM sure sounded good.