My first impressions were pretty good. Cinnamon has a well designed interface, is friendly to multi-head setups, and is obviously pretty slick in general. Fortunately for my ego I correctly predicted that becuase first impressions are generally a little crunked up, I merely had yet to run into whatever annoying idiosyncrasies existed. And I was right.
I think Cinnamon/Gnome3 really could be a successor to Gnome2/Mate. It just needs to sort out the issue where it randomly starts crashing left and right every once in awhile. You know, you'll be going happily along, and then BOOM. Everything freezes except the mouse, which can't do anything. Or maybe the entire X server just randomly restarts itself. Or perhaps the computer is in a lippy mood, so the desktop environment goes away, leaving you with no menu's, no window borders, no drag-select, or any of those other nifty things young whippersnappers like myself are used to.
This really torqued me off, especially because I didn't want to have to burn another DVD and re-install just to try Mate. I mean, I thought the idea was to get away from Ubuntu's stupid decisions like separate editions for separate desktop environments. Fortunately, I kept my head on and successfully attempted just installing Mate packages next to the Cinnamon ones. Apparently the separate editions are just for people who are really really lazy or just don't want to have to worry about installing packages.
So...Mate. Apparently Mate is made out of vintage barrel aged awesome. I have been unsuccessful in making it break. It does what I think the best desktop environment would do: get the crunk out of the way. In my opinion, a DE is there to make your windows go 'yay' and your desktop go 'yipee', not to replace them. But if you happen to have a setup different from mine in whatever way that made Cinnamon crunk, you can use it just as easily.
If it seems like I'm spending a ton of time talking about the DE, it's because there's not a ton to say about much else. Linux Mint mostly stays true to its policy of basically being Ubuntu with less bloat, more configurability, and a better interface. All in all, Mint 13 is pretty awesome.