I just deployed the Openstack Train version of Horizon to horizon.wikimedia.org. I've been testing it a fair bit in codfw1-dev but it may yet exhibit bugs and/or new weird features that we don't actually want to support. Please let me know if you see any weirdness there.
So far there aren't any big advantages to the new code (I was hoping it would be faster but if it is it's not by much) but at least one piece of our stack is pretty much caught up with the upstream :)
-A