Well, I updated to Mint 15 MATE 64 bit as I could see they finally pulled their thumbs out of their butts over Firefox since the last LTS came out.
(Mint wouldn't use the Firefox name or icon because the French dudes were feuding with Firefox a bit over not getting paid per hit or some such nonsense).
Mate is Gnome with future tools, but not the official Gnome 3.x exactly as the Gome folks went off into the starry starry night and nobody chose to follow them into that great nebulous starry beyond except the folks at Red Hat. As a matter of fact the only Gnome developer people that are left are the ones who actually WORK at Red Hat, so Red Hat has inherited their very own personal desktop now, built the way their folks like it ..... good for them.
So you could say Gnome actually forked 3 ways, the offical "Red Hat" Gnome 3.xx, Gnome as Mate and Gnome as Cinnamon. Cinnamon is soon going to cut all ties with the official old gnome base as of the next update and become a total inhouse thing with the Mint folks. Lots of work there, but apparently Mint is popular enough to support its own desktop development team ...... good for them.
Mate is also becoming completely independent, but will still keep whatever good bits of old Gnomishness that are still considered worth while.
Mate is actually used by 3-4 distros now and it seems to be the surviving as an independent open source project "child of Gnome" that will actually go forward into the future as an old style open source project.
You can't really spit on the differences between Mate and Cinnamon right now as Linux Mint is still polishing both up to be about equal in all things, but eventually they will pick just one and roll forward with it.
I liked Gnome 2.0 and I'm very sorry they picked a team leader that led them off the cliff and thy were stupid enough to go follow him there.
(even though Torvalds and others told them it was stupid and a total disaster ....)
The ones that balked right at the crumbly edge of things now work on the Mate Project.