Definitely a refinement. The system seemed to be running faster and the only problem we had was having to update the apps still incompatible with this new Mac OS.
The upgrading process was straightforward although it may depend with your internet bandwidth. Once the software were downloaded installation would take another 30 minutes and a couple of boot up after which everything should be up and running.
So far, I have yet to come across any major glitches. The apps, including my EVE Online game seemed to be running great. The old Aperture - which was rendered obsolete - was OK as well.
I have managed to get all the computers upgraded yesterday except for Anita's Mac Book. That may come later then. So far, so good.
