to gianluca:
From my perspective, there is so much enjoyable music composed in the 20th century, not just string quartets or by Americans, in a wide variety of styles, that it really isn't useful to denigrate an entire group of composers simply because you don't care for them. Unless you had particular criticism for them, I usually find it best to just accept that you don't care for a particular composer or style and MOVE ON. Who are you to say that any one composer is better than another?
When I hear blatant expressions of how a composer is sooooooo great and how other composers are trash I can't help but roll my eyes, think "that's nice...", and go read something else.