Looking for a GNOME 3 distribution that sticks to GNOME upstream is very difficult in a way. I like Debian, Ubuntu and the debian-based distributions out there. If you are a user that have come from Fedora to Ubuntu GNOME there’s a high chance you will see that there are differences between GNOME upstream and GNOME offered by Ubuntu.
Ubuntu does quite a lot of patching to offer their main flagship which is Ubuntu with Unity. Unity itself uses a lot of GNOME apps like Nautilus, gnome-control-center, etc.
The problem comes when you want something very specific like wanting the upstream version of Nautilus or gedit, that’s where you realize Ubuntu GNOME is sort of crippled not by the team that develops it but by Canonical itself. There’s just no way of providing upstream packages without it being altered or just using the PPAs which maybe ships vanilla packages.
Thus, it actually makes Ubuntu GNOME not a fit to the people who wants a true GNOME 3 experience.
I don’t particularly have any strong feelings on how Canonical/Ubuntu developers are handling these things. I believe that the Ubuntu GNOME team is great, the only way for Ubuntu GNOME to undo the patches is by setting up a PPA for each official release, which is totally feasible.
That said, I’m just contemplating on jumping to Fedora 22.