I guess he was talking about usability, not the tech behind it.

Gnome/kde/unity all looks and feels good in one area and bad in another. People disagree about what's right with them on a very fundamental level. Juggling between the user experience and maintain the tech behind is has clearly taken a large toll on these desktop environments.

On the other hand (I guess from an average user's perspective) Elementary feels very cohesive. It feels like the one destro has a much nicer balance between the tech and usability.

But it also has its caveats. If I recall correctly, you can't minimize apps on Elementary, you can only close them...