Over the past two years, I've done a pretty complete upgrade of my system, and have encountered this same dilemma: some recordings I've always liked sound better, but others sound worse. The most recent instance was last weekend, when my wife and I had another couple for dinner. This other couple used to be pretty interested in high-end audio, and they wanted to hear some of the newer, re-mastered LP's I've bought recently. After listening to several of them, they agreed that most were an improvement over the previous versions, but not all of them.
Then I pulled out some CD's, one of which was the album titled "People Time", with Stan Getz and Kenny Barron. I've liked this album very much in the past -- it was the last recording done by Getz before he died of cancer, and it contains some very poignant, even searing, music. However, on my upgraded, higher-resolution system, the sound of Getz's sax was often very shrill, nearly piercing. It was hard to listen thru the sharp-edged sound to get to the heart of the music. Barron's piano sounded fine, however. The CD is on the Verve label, which normally has pretty good sound on their jazz releases, so the audio quality came as an unpleasant surprise.
I hope this thread gets some responses, because I'm interested to hear what others have to say. I will take some time today and sift through some of the LP's and CD's that have sounded either worse or better than I remember (as heard on my previous audio systems), and post the titles and an evaluation of their sound quality.