I've got a few SACDs and do think they sound slightly better than the CD counterpart. Also got some SHM CDs which have definitely been tampered with, ran them through Audacity only to find most of them show signs of serious clipping.Think I’ve got three, couldn’t tell the difference. got a couple of hd-cd, no difference.
bought a couple of shm-cd and they were noticeably different. I wouldn’t say better, just different.
sounded like they had been remixed rather than improved.
redbook done well is excellent. No real need for the other formats.
(kinda how I feel about hi res streaming)