Since Natty Narwhal, which I found to be an elegant and beautiful new interface after a few tweaks*, I have found subsequent versions of Ubuntu to be frustratingly disfunctional.

Quite unfortunately, there seems to be a fashion of removing functionality in an attempt to make GUI's more ‘discoverable’, but ‘discoverability’ is a one-off issue that can be achieved without making software unproductive by educating users with a stunning walk-through showcase demonstration or interactive tutorial. This is how good strategy games make themselves ‘discoverable’, without sacrificing functionality.

Later versions of Unity have been too repulsive for me to upgrade from Natty, but although Gnome 3's shell now looks far more appealing than later versions of Unity, Gnome 3 also has huge issues.

Evaluating Ubuntu-GNOME, so far I've found these issues:

• No appmenu by default.
• Nautilus has significantly regressed. (Also applies in Unity)
• System Settings is disfunctional. (Also applies in Unity)
• No world map of timezones and daylight. (Also applies in Unity)
• Haven't yet found a way of customising the date format to RFC 3339.
• More windows refuse to maximise. (Also applies in Unity)
• (This list isn't complete, still evaluating...)

The first 3 points are each show-stoppers for me. I'm just not yet managing to find good enough reasons to upgrade downgrade from Natty.

* Tweaks for Unity in Natty: remove overlay-scrollbars; reduce launcher icon size; change reveal mode to top-left to avoid irritating accidental reveal whilst keeping speed.