In reply to Glyno:
A note to any graphic designers/typographers out there.
Don't install yet if you are a QuarkXpress user.
They are still working on the 2015 version to make it compatible with El cap.
Mind you, I'm still using Quark 9.5 on Yosemite which is 'unsupported' It works fine.
Quark 10 is however supported on Yosemite, but not on El cap.
Progress eh?