The better is your audio system, the closer it takes you to all pros and contras of a particular sound recording. From there, it is a matter of a taste which kind of sound you like more (I personally like both, tube and class D amp sound, i cannot say which one i like more, but i admit that a SET tube amp may deliver a most realistic sound). And a few thousand dollars upgrade in tour digital stuff will have less influence on the SQ of your system than the quality of the sound recording of a particular album.