I bought this case for my Asus 970 Pro Gaming/Aura, great investment, so damn easy to set up, cable management was a breeze. The Corsair 600C and the Phanteks Enthoo XL DS are, so far, the best cases on the market.
I wouldn't say the Phanteks Enthoo XL DS is a bad case but its not the best, its use point is to small and niche to be considered among the best. It is however, among the best at what it was designed to do, hold two independent systems.
Just an observation.