Make sure the metal you use for your cpu block is compatible or a match, so you don't have corrosion going on in your water cooling system. Buy the waterblock for your GPU according to the metal you are using for the other waterblocks. Mixing metals results in corrosion.
Now I'm wondering, since this is a 570 block it should work with my card right? It is a 570/580 block - I don't know if that makes a difference or not. I like this block because it is copper, and I think it would work well with my CPU-370 CPU block.
I am pretty confident they will all fit my card, but I can't decide on which to get, I see that the hole edition of the GPU-X got better reviews, but I'm not sure, as the DD block got great reviews, too.
Well, that's why I separated them specifically - they aren't really that good, especially for what you pay for them. Among the rest, there isn't really a true differentiator other than price and looks.