Coming back to my opinion on some reviwers: I forgot to mention those who, because just they don't like a piece, they just find it bad. This is also unfair.
This is a pet hate of mine. Just because you like something doesn't make it good, and just because you dislike something doesn't make it bad. I think most critics are not actually capable of judging the quality of a work, and just go by personal taste. Plus, of course, the assumption that a composer outside the standard canon must be bad, or he wouldn't be neglected. Whereas anyone famous must be good. It's the same in the visual arts, and its refreshing when you see an art critic lay into, say, Damien Hirst. I have a theory that Picasso, in his late years, actually tried to produce bad drawings to dare art critics to call him out - which none would dare do, of course.