Ok, now after trying it for a while and really liking it there are (of course, beta) some issues.
Workspace browser gets nearly useless. When itīs fullscreen you canīt drag and drop anything into the edit window except you make a split fullscreen window with both windows side by side. In this case it would be nice if the workspace browser would be a floating window.
When closing a session, ProTools keeps fullscreen spaces/desktops which were open before closing and they all appear black. This is just cosmetic, but it could be better
And with the new El Capitan function to auto hide/show the menu bar, you get a little more space for ProTools, handy for smaller screens!