Unity really was a great project.
KDE 6.6 is great to me, but there are some quirks I have found. Their "peek at desktop" feature is annoying, I want "minimize all" but you have to do some scripting to enable that.
I've noticed that clicking the network button to see wifi status shows traffic rate, and that seems to lag and I suspect it has an impact on throughput.
I'm interested in Cosmic when it matures some more.