Until a few days ago I was running Fedora 16 (KDE) on the X220 and it ran perfectly. Ubuntu 11.04 was why I moved to Fedora in the first place.
On the X220, 12.04 has run perfectly. On the X120e however, which also ran Fedora 16 (KDE) previously, I have to admit that 12.04 was sluggish. I haven't narrowed down the problem - but I feel it might have something to do with graphics performance -- which feels strange, since I always historically associated KDE with sluggish performance due to graphics, not Gnome.
On the X220, 12.04 has run perfectly. On the X120e however, which also ran Fedora 16 (KDE) previously, I have to admit that 12.04 was sluggish. I haven't narrowed down the problem - but I feel it might have something to do with graphics performance -- which feels strange, since I always historically associated KDE with sluggish performance due to graphics, not Gnome.