I owned a CS600 and currently have a CS600x in my office system. The Cs600x is better in every way but read up on the cs600 for speaker matches, its just a better and improved version. To me it seems to have more presence and snap. Maybe some power supply improvements, but it isn’t so different that speaker recommendations that were applicable to the 600 no longer apply. I enjoy Devores with the Leben but I have also connected it to my Wilson Sashas and it did a surprisingly good job, just a little loose in the low bass.