Many CDs have mixed reviews in regard to their sound quality.
Much depends on the audio equipment used by the reviewer. Many highly regarded components have some problem or another in reproducing sound in a natural and realistic way.
I have made component changes from time to time and found changes in which of my CDs sound good and which were bad. There is an interaction effect.
However when you finally eliminate problems from your equipment, you can hear a natural instrumental timbre and realistic presentation from many CDs - the number of bad ones reduces, and then they are mostly bad in parts.
I have achieved this in my systems at a very low cost.
One reference quality CD I use to evaluate components and tube changes in my system is Prokofiev's "Romeo and Juliet" on Philips conducted by Gergeiv. The instrumental timbre is so natural here, when my tube set up is the best sounding one in terms of naturalness and realism. Changes in timbre, to varying degrees of unnaturalness, are readily heard by changing components or tubes in my amp, using this recording.
However, though rated as excellent sound quality in one review, this CD is rated only just slightly above average in another review - a big discrepancy. I am sure my assesement is correct, in agreeing with the former review rather than the latter, and would bet the latter reviewer has problems in his/her system that are unrecognized. Many people do, which is why they are always upgrading in search of the holy grail. I did that myself for 50 years, starting at 10 years old.