I have had 4 different ORACLE DELPHI decks, first was MK IV w/ (at the time new) hard acrylic mat and stiffer spring suspension. Frankly, it sounded awful no matter how carefully I adjusted the suspension and fine-tuned it, I got perfect up and down bouncing but not a good sound.
I switched it with Goldmund Studio but didn´t like it either. Because its floating flimsy suspension system is a mission impossible, almost made me nuts, well young and foolish I was...
Second was MK III w/ original GROOVE ISOLATOR Black/Gold edition but unfortunately w/ a bit flawed suspension tower positioning so it was another mission impossible to get a fine-tuned suspension not to mention a perfect sound. Third was MK II and everything fell in place, great sound. Last was MK II.7 Black/Gold edition w/ GROOVE ISOLATOR and hyper sensitive (soft) suspension. Sounds absolutely wonderful, easily outperforms Goldmund Studio and Luxman PD444 superlative vintage DD decks. Like day and night.
ORACLE DELPHI MK II/III namely w/ GROOVE ISOLATOR and sensitive suspension is the finest they ever did IME.