I just upgraded to ownCloud 7 with a dead simple
apt-get update && apt-get upgrade
This is just in time for a trial roll-out at the office. Most notably, I'm super happy at how the new Files sidebar clearly delineates between your files, shared with you, shared by others, shared by links, and external storage. One of my biggest hangouts with ownCloud 6 was that my users would just created their own files and share them instead of having them properly set up via external storage, but this simple interface change will make the difference far more obvious.
Looking forward to seeing what else is new...