KDE 4 to 5 was very smooth, though I waited ~3 months for reports from others before I jumped. :)
It feels like KDE 5 was focused primarily on polish rather than new features. (I honestly can't think of a feature in KDE 5 that wasn't in KDE 4.)
My only complaint I have for KDE 5 is that the system tray applets can occasionally disappear after multiple sleep/awake cycles on my laptop without rebooting, but right-clicking on the tray, disabling an applet, then reenabling it causes anything missing to reappear, which is probably the most minor thing someone can have for a desktop environment!
Oh, and people confuse my KDE laptop for a Windows laptop because it looks a lot like Windows Vista by default.
Yeah, KDE 4 looked a lot like Vista, KDE 3 looked like Windows 95, and KDE 5 looks like Windows 10.
Not complaining, I think it's nice that at least one major DE is consistently taking ideas from Windows when everyone else tries to copy the latest Apple product.
It feels like KDE 5 was focused primarily on polish rather than new features. (I honestly can't think of a feature in KDE 5 that wasn't in KDE 4.)
My only complaint I have for KDE 5 is that the system tray applets can occasionally disappear after multiple sleep/awake cycles on my laptop without rebooting, but right-clicking on the tray, disabling an applet, then reenabling it causes anything missing to reappear, which is probably the most minor thing someone can have for a desktop environment!
Oh, and people confuse my KDE laptop for a Windows laptop because it looks a lot like Windows Vista by default.