That is so subjective though. There are some people, for example, who would pass off Keith Jarrett's solo improvisations as mediocrity, others who think it is great. Critics vary so much in their opinions also. If there were any sort of objectivity to whether music is good, critics would have a valid role, I think. But since that isn't the case, they basically are just hot air factories, whose sole purpose is only to annoy those who truly appreciate music for the sound of it, not for a bunch of stagnated traditions, rules, and prejudices.
This is especially true since the advent of avante-garde music. Modern music has been so long trying to push the boundaries of objectivity in music so far that all we have left is subjectivity. For a while, we had "defined" objectivity in terms of the simplest tonal relationships, and had defined it by maintaining integrity of voices within that context, by further defining independence by mostly contrary motion and use of the most "independent" sounding intervals, 3rds, 6ths and 10ths, etc. But since we've unravelled all that and proven that good music does not need to follow those rules, we've eliminated any basis upon which critics can actually base criticism, except their own opinion: Did they LIKE the music they heard, or did they not? It is a very subjective judgement, I believe. Thus, what they say is worthless. I'd trust the opinion of a normal man over that of a classical music critic any day. (because, let's face it, Metallica is more enjoyable than John Cage...to most people anyway)