It's been great almost since I started using it.
I started using it exactly when 4.0 came out, because that's when I started using Linux and I thought learning 3 didn't make sense. But 4 only got stable around 4.4 I think. The problem was that 4.0 wasn't intended to be for end users yet, but distributions didn't realize that and packaged it right away.
KDE didn't repeat that mistake. 5.0 was almost completely smooth sailing (some applications took a long time to port and looked ugly, that's it), and 6.0 was completely seamless.
Ooo damn that sounds exactly what I'd like to try.
On the other hand I feel like I'm too old for this shit. My system works fine, I understand everything, and things rarely break and never in an unrecoverable way.