I can't live without the Super+[1,2,3,4...] shortcuts.
One of the most noticably broken parts of Gnome Shell for me is that my Pidgin notifications/alerts seem to be broken. They neither flash the item in the taskbar, nor give me a popup to let me know that a new message has arrived. I had an extension to fix this, but that has since broken upon Gnome version change. There is a messenger integration into the user account menu in the top right, but there is no way of changing the client from the default to Pidgin.
I only use Gnome on my travel laptop, so I get little snapshot peeks at how it's going. I've had these problems I've mentioned for quite a while now (and many more besides), it only seems to be getting worse. The Gnome devs seem to be completely ignoring the community and charging off down their own path of weird unusability.
For my main desktop I just run AwesomeWM, which is almost completely pain-free and gets the hell out of my way.
Never made sense to me.
Much less cluttered than unity (most of the time you just have a single black bar at the top of the screen) and handles workspaces nicely.
I never liked gnome 2, though, so take my opinion with a grain of salt.
The difference between Gnome and Unity is that if there's something you don't like about the former, you can install an extension to fix it. If there isn't an extension, you can write one - at least theoretically.
Anecdotally, that sort of shifts the blame for missing functionality around. It's no longer "my wm is missing x" it's "I haven't written x for my wm yet."
No signs of anyone fixing them either, it's been 6 months since my Pidgin extension broke :(
My main point of contention is that Unity's dash isn't fast enough for me and I am tired to dig the registry to get rid of the on-line suggestions. But overall I think Unity has a better App/Window management than GNOME (the dock is much more functional for instance). So no 14.04 for me. Except if performances are okay and if the team pulling Ubuntu GNOME show good support.
The trick is to use extensions. In particular, the "shellshape" extension for GNOME Shell is a pretty good approximation to sane tiling window managers.