Mint's packaging and documentation is significantly worse than Ubuntu's. There is no reason to use Mint and not Debian or Ubuntu, except that you are interested in Cinnamon (which I have never once found to work)
Right now on Debian, every desktop sucks out-of-the-box - I've been bouncing around them trying to find something that will satisfy my preference for a traditional desktop. As Debian doesn't do much in the way of UI customisation, so this pretty much means every core desktop sucks at the moment without a downstream maintainer nailing it down properly. XFCE is a little coarse though it would be usable... if only it didn't stop my laptop from properly resuming from sleep (other environs don't do this).
I've used Mint's LMDE distribution and liked the desktop in it, but the community around it doesn't seem too big, which makes me a little nervous.
If what you want is a "traditional desktop" UI and you're running Debian, ISTM you'd have plenty of options. You can install a complete environment (GNOME 2, XFCE) or one of the many tiling wm's (awesome, dwm, xmonad, &c).
As far as I am aware, gnome 2 was losing maintainer focus. Certainly right now, it's hard to clearly find gnome 2/debian sid results on google - something that is important when things go wrong. XFCE is somewhat coarse but usable... if only it wasn't the only desktop that prevented my laptop from resuming from sleep. The tiling WMs I haven't installed, but when looking at their webpages don't seem to be traditional desktops - floating windows, ability to put thing on the desktop itself. The latter item is important to my workflow, and I can't understand the religious zeal with which people think that the desktop must be clear these days...
Right. Correction to my comment above: I meant to separate the tiling wm's out of "trad desktop" distinctions: I don't think the tiling wm is what most users think of when considering desktop UIs. Still, I from what I've seen wm's like awesome or xmonad do a good job of maximising screen real estate and make everything keyboard-centric, which saves a lot of time for developers.
XMonad is really great, provided you're willing to spend some time learning Haskell to configure it, which isn't a trivial task. It's in my book a very rewarding experience.
