I had a couple of the re-mastered Bob Dylan 24k gold CDs a while ago. The regular CDs of his classic stuff sound like absolute crap, especially compared to the LP. I'm definitely biased towards LPs, but this was a difference a deaf person could hear.
They were much clearer than the original CDs, but in the re-mastering process, they over-emphasized the bass - making it all just sound "off." It's like they took the original recording and made it sound how people would like to listen to it "now" rather than how it was recorded. It just felt wrong that they altered the original sound... I can live with listening to the stereo version over the original mono, but this just seemed heretical... it lost some of that "wild, mercurial sound" that he was known for.
Long story short, I think the re-mastering process for old CDs definitely has some credence, but a whole lot depends on the person at the helm.
If the original CD master was less than stellar, I think it's definitely an improvement, regardless of editorial adjustments. Almost anything produced before the early nineties would probably benefit from this kind of treatment. Just be warned that there may be "improvements." Now, the Dylan CDs I mentioned earlier retailed for almost $30, so if you are paying $12, then they probably didn't pay a guy a lot of cash to screw it up
Now I 'm going to get on my soapbox... if you want to hear the real original album the way you remember it, pick yourself up a good turntable for ~$300 US, and then a copy of the record at a thrift store for $1. After a good cleaning, it will sound better than the CD ever did.