I know this is an old thread, but.....
I've read all sorts of stuff from many sources about the improvements in CD players over the years - oversampling, 96khz, 192khz, better DAC's etc etc. I am very used to listening to music and have been listening to digital sources since they were introduced. These days I run a small recording studio (after 2 decades as a professional producer working at some of the very best studios in the UK)
I have a few cd players, Sony 502ES, Yamaha CDX 1100, Philips CD 840, and a DVD player by Toshiba which has been very highly rated for its sonic qualities. All the older players sound better than the Toshiba - more full bodied and more tonally accurate. The differences between the 3 dedicated CD players are very small sonically.
I recently auditioned a Rega Apollo and a Cambridge Audio 840CD at home, through my own system, for a few days. These are highly rated more modern machines, the Cambridge being at the top limit of what I wanted to pay for an improvement over my already excellent sounding machines.
Rather than their being a 'night and day' difference between these new machines and the older ones, there was barely any difference at all. Both were slightly brighter sounding than my old players, but not in a pleasant way, and the Rega lacked control of the bass compared to all the other players. There was no 'lifting of a veil' or huge improvement in soundstage at all. These were blind listening tests conducted by my long suffering but (thankfully) musical wife.
I am listening through a fabulous system, with vintage but amazing speakers (Kef Cantata 3 way floorstanders with an exceptionally flat response). These speakers easily and explicitly show up the most miniscule differences in the sound of the various different amps I have.
So...I'm not sure about the progress that has been made with the CD format. If you forget about specs, sampling frequencies and supposedly better DACs and use your ears, then good old stuff is at least the equal of modern stuff IMHO. I will not be spending £700 to gain a little more (an absolutely fractional amount) of top end at the expense of tonal depth and warmth.
I'll shut up now.