i read somewhere that CC does not support virtual copies? so images that are in more then one album will have several copies in the cloud?
or how are different versions of the same file (different looks, crops,....) handled? different albums containing a subset/edit of a larger album?
If you want different looks, they're real copies right now, rather than virtual. I'd hope that will change in time, but just one to be aware of. You'll find it in the right-click menu.
Just putting photos in multiple albums doesn't duplicate them, so there's still just one copy in the cloud.