Corona's displacement when set to world size, is no better than max displacement modifier and when set to screen it's useless in baked form. So what's the fuss about?
In screen mode it's not useless to me if you are working to a predetermined camera/resolution. Consider for instance a heavy-poly object which is only partially visible.
You could go manually splitting the object at the edges of the camera but I'd rather use this method. It's only a tip after all, so nothing gets changed.
Also, considering possible benefits in world mode, doesn't Corona's displacement calculate adaptivity based on the detail in the displacement map as well?
I honestly don't know if it works in this way or not (have to go back and look at some of the threads from when adaptive displacement was introduced) but theoretically this would make it more efficient than Max's modifier.