I use Ubuntu and I can't stand unity. It's far too easy to do `sudo apt-get install gnome-shell` and do `sudo add-apt-repository ppa:gwendal-lebihan-dev/cinnamon-stable; sudo apt-get update; sudo apt-get install cinammon` and still enjoy the Ubuntu base (community, font patches, etc). I've bounced around between many DEs lately. Elementary is really great, especially when I was just coming from OS X, but I've been shocked at how nice Cinnamon is.
xfce improved my experience of ubuntu considerably as well and the install was trivial too (sudo apt-get install xubuntu-desktop). alt-tab works there!
I use Xubuntu, it's probably the best way to get the good parts of Ubuntu (the good package selection, proprietary software support, and OOTB hardware support) while also having a good UI.
I don't know why people hate it, I love it. It gives me so much more visual space.
For example, with Unity I was able to start using Virtualbox VM's maximized instead of full screen, which is so much more comfortable. The host has the sidebar hidden (shows on hover), and the guest has it always visible (as hover wouldn't work for a guest). It really makes a great use of the visual space.
The alt-tab behaviour is borderline unworkable for anyone who's used Windows or Linux windows managers before 2011 and is trying to work with a case like several terminal windows and a browser window.
My GNOME 2/XFCE/MATE setup has one bar on top of the screen and that's it, I'm finding it is pretty good for screen space even on widescreen laptops.
The alt-tab thing I think they copied directly from Apple (not necessarily a good thing).
The thing that really hurts about the new alt-tab is that it breaks my mental stack. On Windows, in KDE etc I can switch back and forth between two browser windows easily. On Mac and Unity you either have to decide of your last app change was an app change or a instance change.
