Ran the upgrade to Fedora 22 yesterday using the fedup utility. With the Fedora 20->21 upgrade, a --product option was added to fedup to allow the user to select whether to install the Workstation, Server or Cloud version. The latest version of fedup does away with the --product option.
A little over 4200 packages got upgraded on the computer, so the download and install took a while. I let the downloading run overnight, and rebooted to do the install while I was at work. When I came home, a new Fedora 22 login screen was waiting for me.
First thing I discovered upon logging in was that my old KDE 4 Plasma environment was no longer valid, so I had to start off completely fresh with KDE 5.
The second thing that struck me was KDE 5's appearance and icons are flat. Solid colours, kind of old school feeling not unlike the icons used in Google's Material Design.
I also can't add frequently used application icons to the KDE 5 panel. I don't know yet if that's just been done away with or if I have to add a new widget to the panel.
So far most of the changes I've noticed are cosmetic. I've been mostly just exploring the new KDE 5 desktop and getting things close to what I had before. Then I'll be able to dive in a little deeper.