I'm just trying out Linux Mint Debian Edition and the best part about it is how fast it is. The desktop is super responsive, almost feels like a new fresh Windows machine in that respect. User switching is also super fast and works perfectly, something that Ubuntu had never quite mastered. Most importantly, however, is the fact that it is not using Canonical's Unity, but instead it is still using Gnome 2.
It's been a long time since I have used an almost-pure Debian distribution but it feels good to be back. My Linux evolution went something like this: Redhat->Corel (debian)->Mandrake->Debian->Gentoo->Ubuntu->???. I will definitely move to something Debian-based or possible Gentoo. I may keep the LMDE on my laptop and put back Gentoo on my desktop. Unity is just plain awful and should never have seen the light of day. Ubuntu was great when it first started and it was basically a Debian derivative that just worked. Nowadays Ubuntu is a different beast. It's slow, awkward, cumbersome, bloated, and I can't stand the fact that they are forcing Unity down people's throats. I'm positive that Unity will be a failure in the end.