Everybody knows that Ubuntu 11.04 will come with Unity (Unity is a compiz plugin) as default desktop environment. But, now, a few weeks before final release, some Ubuntu users are not satisfied with a current Unity condition so they propose GNOME again as a default desktop environment.
A message to developer mailing list indicates that GNOME could become the Ubuntu primary choice again and there will be a public debate for future Unity development. This is the reason of many problems with Unity stability (systems with Unity crashes quite often), large list of irregularities, hard to find options, icon behaviors, etc..
However, despite all critics, the majority still supports Unity, hoping that Unity will become more stable and useful with releasing the final Ubuntu 11.04 version at the end of this month.