Running on a 2013/2014 MacPro with the D700 video cards and updated to 10.9.4.
Just exported 5 interview clips with over an hour of footage using Resolve 11 Beta running in Mac OS 10.9.4. No issues at all. Worked perfectly. Source footage was shot on a RED Epic and a 3D LUT and a curves node were applied. Initial grading tests worked well also, and I encountered no issues with playback.
So far, (knock on wood), everything appears to be back to normal running Resolve on these beastly machines.