Which one is the faster and will I get all the features of Ubuntu on them? I've done a little homework too on it, I think xfce will be the better option. My pc specs aren't good enough to handle Unity, as it hangs very often.
Obviously LXDE. It is even lighter than XFCE. LXDE uses about 110 mb of ram when idle while XFCE is a little more bloated, taking about 200 mb (based on my experience)
XFCE. It have more GUIs while LXDE requires you to modify configuration files in your own in some cases.
Both are configurable, but it depends on how much you want to play with it. It is less configurable than KDE or GNOME, though.
Via the software center everything is easier. But I recommend you use lubuntu-desktop for LXDE or xubntu-desktop for XFCE. (Since they've prepared most of the stuff for you)
