Hi
I have been using Ubuntu GNOME 13.10 development branch for quite a while. I had very little problems and most of those that I had were bugs that are present in normal Ubuntu as wel and I reported them in the ubuntu bug tracker as such.
The only noteworthy problem I have is that I can't get nvidia optimus to work.
I made a thread in the nvidia forums since I suspected it had something to do with the drivers, but I recently got it working by running it by using unity, lightdm and nvidia-prime. (Which I don't want to do since I want to use gdm and gnome otherwise I could've just stuck to regular Ubuntu)
https://devtalk.nvidia.com/default/topic/616969/linux/xserver-fails-to-connect-to-screen-after-installing-nvidia-driver-nvidia-optimus-gtx-675mx-ubun/
nvidia-prime is supposed to set it up correctly to use my nvidia card, but it relies heavily on unity and lightdm and changes lighdm settings (and doesn't work with gdm) so that it detects the display.