I have a lot of late 60's and on rock in the original vinyl. As time went on and my turntable wasn't hooked up I would buy the early CD releases of the same albums. What I noticed was the early CD releases from the mixed for vinyl masters were mostly horrible. When the same albums' remastered CD's were released I would buy those and for the most part they were pretty good. I especially liked the HDCD versions (I have a player that decodes them). I haven't delved into some of the other Hi-Rez formats so can't comment.
When redbook CD's were released from mixed for CD masters the quality was pretty good (until we got to the Loudness Wars as others have stated) and I think then you were looking for specific pressings, usually from different countries, (also, as others have pointed out).
I think as time went on improvements in digital recording and playback equipment also played a significant role but I don't know of a specific time frame when there was a sea change that could be pointed to.
When redbook CD's were released from mixed for CD masters the quality was pretty good (until we got to the Loudness Wars as others have stated) and I think then you were looking for specific pressings, usually from different countries, (also, as others have pointed out).
I think as time went on improvements in digital recording and playback equipment also played a significant role but I don't know of a specific time frame when there was a sea change that could be pointed to.