Yes, it's visually wild. Yes, it's beautiful and violent and very, very strange. And yes, I agree with Ebert when he writes that Sin City "uses nudity as if the 1970s had survived."
He captions the opening shot, "There are a million stories in Sin City, and this is several of them." That's even better than it looks, because the opening and closing scenes don't obviously cohere with the rest of the (tangled, braided, convoluted) plot.