The weight of Ubuntu? Redhat, Solaris and several other Linuces/Unices use GNOME, too. I think it's far more widespread than KDE which was primarily used by Europe-based distributions, e.g. SuSE (now Novell).
In the end it shouldn't be a matter of KDE vs. GNOME vs. <other>. The VFS system should be a common implementation shared by all desktop environments.