If you like and use Gnome Shell, then yes, is a good idea to switch to Ubuntu Gnome Remix. Actually UGR is nothing but an Ubuntu with Gnome Shell and GDM, without Unity and with kinda a different set of applications pre-installed. You can easily make UGR identical to Ubuntu and the other way around -at least in this version (12.10).
In my personal opinion, the reason to switch (other than you have a ready Gnome and you don’t need to install Shell, GDM and set GDM as default) is that UGR is a community project, with future plans to be under Canonical’s support in 13.04 -but it will still remain a community driven distro.