I own a Zero SR4 rack: https://www.adonacorporation.com/zerosr4.html . I like the fact that one can position its shelves literally anywhere within its confines. It does a great job of supporting and isolating my 120 lb. turntable. And as mentioned above, Adona's shelf isolation design seems to be theoretically sound.
I agree with your assessment that they are high quality at a reasonable price point.
I agree with your assessment that they are high quality at a reasonable price point.