Amtico is a great product, the only thing I would say, is get a professional floorlayer to install it. I deal with Amtico a lot and have seen some absolute nightmares, all created by fitters who don't understand the product. Floor preparation is paramount before laying any of the products, get that wrong and it will always look a mess.
meadowhog's right, Karndean is good but you get a much wider choice of patterns and styles with Amtico and the reproduction is more realistic. Wear quality is about the same at the top end of Karndean but there again, so is the price.