The first time I noticed a difference between mastering was the MFSL release of the Getz/Gilberto CD. When I first listened to it, I was stunned by the difference between it and the original Verve release. It was like they were mastered by completely different tapes. When I rip the MFSL to CD, it sounds like the Mofi. I also have made rips of Hi rez files made for me from LPs to black blank discs with great sonics.
Remastered CDs, HDCDs, SACDs
CD is my only source. My album collection is somewhere around 800 discs. I have found significant differences in SQ (sound quality) comparing original releases to remastered releases. To my ear, Bob Ludwig was the best engineer for that.
I was speaking with a local recording engineer and mentioned how much I liked Bob's work. He replied Bob boosted 2 dB at 150 Hz.
In order of SQ (worst to best) my rankings are original CD, original HDCD, remastered CD, remastered HDCD, original SACD, remastered SACD.
Those rankings are usually the case, though occasionally they may vary.
Happy listening to all. Enjoy the music!