Personally I'd say MacOS 9 was the peak (ignoring its instability).
Things like:
* the filesystem root being the desktop - so you started navigation from the first thing you saw when you switched the computer on
* the way the finder remembered the exact layout of your folder windows (if you've not experienced it, it's hard to explain why it's better - but Windows Explorer and the current Mac Finder are both file browsers, whereas the old Mac Finder *was* your desktop in whatever state you left it)
* kernel extensions being switched on and off by dragging them in and out of the extensions folder
These things made the GUI match the actual underlying system - whereas I always felt that Windows 95 onwards (and now OSX/macOS) hide the workings under pretty layers).
Having said that I also used Turbo Vision in the olden days and it was fantastic.
Things like:
* the filesystem root being the desktop - so you started navigation from the first thing you saw when you switched the computer on
* the way the finder remembered the exact layout of your folder windows (if you've not experienced it, it's hard to explain why it's better - but Windows Explorer and the current Mac Finder are both file browsers, whereas the old Mac Finder *was* your desktop in whatever state you left it)
* kernel extensions being switched on and off by dragging them in and out of the extensions folder
These things made the GUI match the actual underlying system - whereas I always felt that Windows 95 onwards (and now OSX/macOS) hide the workings under pretty layers).
Having said that I also used Turbo Vision in the olden days and it was fantastic.