There's nothing terribly awfully bad about them inherently ... they aren't great for the money, no matter what people say, but if someone insists on buying one, then ho hum. I could say "Get a Yamaha MG, they're as cheap, sound way better and won't have the same reliability issues" but I'm so sick of saying it and having some moron come shoot me down that I dunno if I'll bother.
Their design theft does annoy me, but ultimately if they can do a good product for cheap then they should. It is the buyer's fault if they can't tell the difference between Behringer Truth monitors and Genelecs ...