In analog terms and in many cases the original vinyl sounds better and most often truer to your memory and the original intent of the release.
However since the advent of digital, the quality of the tools keeps getting better and better.
I will make the blanket statement (based on my own listening tests) that 75% of the CDs pressed between the mid 80's to the mid 90's...SUCK!
Well the answer is two fold, number one in many well documented cases, in order to jump on the bandwagon of digital reissues in new market, substandard safety copies of classic albums were used instead of going back to the original masters for digital release. Second, the digital conversion process back in that time frame was abysmal compared to what we have now, as well as our understanding how to master for it.
However, having said that there is a danger in some of the re-masters which we have now where record companies have taken and re-mastered an album to what passes for taste and expectation of now. Meaning many classic albums have been smashed into a brick wall limiter and mastered for the louder, brighter, bass heavy market which is the current trend.
So it does become a case by case scenario where some remasters rock and some suck.
The Led Zeppelin, Black Sabbath and Pink Floyd Remasters are awesome as they are true to the original releases dynamic volume, while some catalogs like Hendrix, The Police and AC/DC have been squashed, brightened and destroyed. Then this gets fixed and you get a set of remasters often only a few years after the other batch.
IE the middle period AC/DC remasters are superior to the current round.
Back on track here, I have the ENO remasters from a few years ago which had the plastic slip case on them and they are far superior to the initial EG eno releases from a decade ago. I would be very curios to hear if these Japan releases are even better.
In general, many re-issues now are getting pretty good as many artists and engineers alike with enough clout are able to control their catalog and resist the louder is better philosphy.
The current Genesis, Bob Dylan, Grateful Dead and CCR reissues are the best that those albums have ever sounded.