I have had the player for over a week now, and it seems to be done breaking in so far from what I can tell. As I stated when it first arrived, it does have a lower noise floor and a blacker background than the CD-55. It also is a little bit
smoother on the top end than the CD-55 was, and is not quite as bright up there. The detail is a bit better as well, maybe from the lower noise floor, maybe just more detail.
I am also noticing a little more body than the CD-55 had as well. It is easy to notice that they are cut from the same mold so to speak, and the differences are subtle but there.
I have had some trouble with the unit tracking discs, but it has not been major. It has stopped playing 5 times now, not a skip or jump, but it has just randomly frozen on random spots on random discs as if on pause. The display just shows the track and minutes/seconds where it stopped, then when I pushed play again, it starts back over on track one just fine...maybe just a small quirk that will go away after time I hope. The drive makes a slight "whirring" noise when spinning as do most computer disc drives, and it can be heard in a quiet room from about 8 foot away, but you don't notice it if the music is playing at fairly low levels. Not a big deal... I hope this helps, and I will check in again in in another week or so as time goes on.