My last experience with Unity was that it just lagged lagged on a machine that could handle windows seven with no hiccups.
Most people with whom I talked about this seemed to have had similar experiences. In truth I've never heard anyone defend Unity.
I have never met a person who called unity slow and unresponsive, but I always read that complaint online.
My dad uses it full time at home and consider it just as user friendly as the windows he uses at work.
I used it on my laptop 7 years ago, and every other update had hardware compatibility quirks. But unless I used the XP that came with that laptop, Windows also didn't have full compatibility.
Well everything is relative I guess. Compared to Windows Vista, Unity is rocket fast. On older machines MATE is much more responsive then Unity without suffering the tweak-ability issues of Lubuntu.
Unity has been responsive for me on a variety of hardware over the past three years. I'd say anything with Intel Graphics or better would be fine. As a generic user experience I think it's better than Windows 7, worse than Windows 10 [for people who like Windows 10]. On Linux, I prefer Unity to Gnome and Xmonad to everything.
No. Still slow and unresponsive, more or less works responsively after reboot and if you kill the hud-service and disable some other stuff, but starts to get to barely working after a bit.
Lubuntu is the most responsive one from the Ubuntu family I think.