What improvements did you hear in going from entry level to high end Audio?

To m e it all depends on "whose" high end audio you're referring to.  Not all "high end" audio manufacturers float my boat.  But when I do hear differences they usually begin with tone, especially the piano.  Once that is right to my ears, other things fall into place.  Soundstage, dimension, separation of vocals, instruments, detail, macro to micro to macro passages, bass detail and definition, more floating of the sound, decay of notes, large scale orchestration layers with dimension, etc.

Happy Listening.