It's like asking if a fiat or daihatsu is better... If you're looking for something cheap that can get you somewhere, but isn't really all that cheap when you actually look at it, cloud II is better than the tiamat.
For that price though, consider proper headphones like HD558 or ATH-AD500X, those tend to be the most popular around, and far better audio and build quality than the tiamat for significantly less. If you need a boom mic, you can either buy a Modmic like item or get a set like the G4ME One/Zero