The post Ubuntu and the Price of Unity from Richard Hillesley, provided commentary and analysis of Canonical's decision to go with Unity vs the Gnome desktop. As summarised:
Canonical's decision to go with the Unity shell on GNOME doesn't come without risk. Mark Shuttleworth aims to unite design with free software, blurring the line between the web and the desktop, and make Ubuntu and free software popular among the kinds of user who have never before heard of free software.
It gives some history of the development of Gnome desktops (interesting of itself), but more usefully includes a link to a previous Shuttleworth interview which set the challenge for Ubuntu to overtake Apple in the user experience stakes. There. Somebody actually said it! RC