I'd like to congratulate the team behind Linux Mint Debian Edition for bringing a truly great desktop-oriented Linux distribution.
After many years of using Debian Stable exclusively on both servers and desktops/laptops, last week I finally decided to switch to Ubuntu. Its philosophy is good - it wants to make things "just work", and also bring regular updates and bug fixes through the life of the 6-monthly (or 2-yearly) stable cycle.
That lasted about three days (I'm really sorry, I *should* have given it more time in the name of fairness. I did try both 11.10 and 12.04 Beta 2 though.)
I like things to just work, and I also like to set up my desktop, panels and fonts just the way I like them. I'm sure you can see where this is going. Unity. It's a nice idea but not for me, for the reasons I just mentioned. (I could go into great depth about how the total lack of reconfigurability is ridiculous, to the point of flat-out refusing to make the launcher-on-bottom an option, and even remove a previously-good option like window-dodging, but others have done a better job at taking apart Unity's problems than I). I am, however, not stupid enough to believe that Unity *is* Ubuntu. It's one of many choices, and all the usual Linux desktop environments, from XFCE to Gnome 3's fallback mode to even gnome-shell are still there. However, there are serious problems with them and it's Ubuntu's fault.
Upon switching to gnome-shell, the desktop theme "looks" broken. The GTK+ theme which worked for Unity tries to work in mutter and with gnome-shell and fails, both in the sense that window decorations now have visual glitches, and that the brown and oranges doesn't look nice with gnome-shell. A good deal of un-configuration, including changing the GTK+ theme and window decorations, even fonts, is required to get something to look more like gnome-shell should look.
Upon switching to XFCE, the same is true. Not only that, the default XFCE configuration in Ubuntu is very much non-vanilla. The bar is across the top, in an attempt to mimic Ubuntu's Gnome interface from versions go by, and the colours and decorations have the same issues as they did in gnome-shell. I don't see why this is even done to XFCE's panels: wouldn't those who specifically choose to install an alternative desktop environment be doing so because they generally "like" the way that desktop environment does things?
Not all of Linux is the user interface, but it is something that has to be right before you can enjoy any other part of it (for a desktop machine, obviously - not a server). Another different reason for my switch to Ubuntu was the slightly more relaxed policy in regards both to pulling in software updates even to stable versions, and to packaging slightly-less-free, but still free-ish, software. Like Firefox, to name a very visible example - which is on version 3.x and is called Iceweasel in Debian stable. Or like any number of audio and video codecs or tools which Debian doesn't like in its repositories at all. Ubuntu had a policy I felt relatively comfortable with *for a desktop system - not for my servers* - a lot of stuff was in "universe" or "multiverse" that was community-maintained, but I could get it and it would be relatively up-to-date. Unfortunately, I think this positive aspect of Ubuntu is let down but their relentless drive to configure things so they look and work pretty in Unity, but are let down in any "non-standard" configuration.
Now to Linux mint. From following their history, they just seem to make overall *sane, reasonable* decisions about all these issues. While gnome-shell and XFCE are themed, the basic point of them hasn't been destroyed to the point of starting to look like something else. I also very much like the Cinnamon shell/UI and the way it works, and the way other distros (like Fedora) are pulling it in as well - it's not just Mint bucking the trend in order to impose their will, but they are developing something useful in response to real user complaints about gnome-shell and now Unity.