"and I wonder whether they represent a significant improvement over older technologies." Of course, it all depends on how you define "improvement". My experience is that more modern players have more detail and clarity than older players. But older players are the equal as regards dynamics and quiet backgrounds, as it should be, power supply design being one of the more mature aspects of audio design. I also think that older players, like the Rega mentioned are, at least, the equal of newer players as regards tonality. In some ways it all mirrors the high end as a whole, some searching for ever increased clarity and some searching for greater tonality. Too bad we don't get both in the same package more often.