Another thought occurs:

Years ago, I met a gentleman from England named James Symington, of the port wine family, at a wine tasting event here. At the conclusion of his presentation, during the Q&A session, a doctor in the audience asked, "How long can one age a vintage port?" Symington looked at him, cocked an eybrow and said, rather dryly, "That's rather like asking, "how long is a piece of string," isn't it?"

In other words, music, like fine wine, is too complex to rate easily or to make judgemental comments about in a vacuum. You have to know all the variables that go into the mix. In the end, past the technical aspects, it is mostly subjective.