If it sounds good, who cares if its unique? I would much rather listen to derivative music that sounds good than unique or original music that bores me to tears. And I would also much rather listen to eighties metal/hard rock rather than the Beatles, just like I would rather read horror/detective novels by modern writers rather than Poe, even though the latter was far more groundbreaking.
See, this is a difficult topic.
The way I see it, there are two methods of evaluating art.
One is entirely subjective--what you like is up to you and I can't really argue with that. If you enjoy Poison more than you enjoy the Beatles, fair enough.
But then there's the whole quasi-objective "general consensus of supposedly informed people" thing, which, while it can't be proven, seems to be given a certain amount of weight anyway.
You can't prove that Hendrix was better at guitar than I am, but if I make a claim to the contrary I won't be taken very seriously.
I have no intention of disputing what you should or should not enjoy...I'm attempting to approximate objectivity by considering critical consensus of the informed.
So when I say The Beatles are better than Poison, I don't mean that your opinion that Poison is more enjoyable than The Beatles is invalid...that's just not really what I'm referring to.