I'm getting a good 10-20fps drop when using Screen Space Reflections (obviously only available to the dx11 version).
So if you are having framerate issues, it's most probably that.
Unfortunate, since SSR is usually a very noticeable visual effect that adds a lot to environments. (Like this http://youtu.be/mub2lKel9JE?t=33s )
I'll wait for a fix, don't need to play this game any time soon.