And honestly, the design has not kept up with the times. For its weight class, it's pretty big, thick and clumsy. The trackpad is atrocious (that's not a problem if you like trackpoints, but my fingers end up hurting after an hour of using them). I also found the x220 quite slow, and the fan spends a lot of time running even with just basic browsing. Battery life is decent though, it probably won't break just by you looking at it sideways, and the keyboard is good - its a classic Thinkpad. But next to a modern Ultrabook it looks quite dated.
However, if I were to spend my own money, the Dell XPS 13 Ubuntu edition looks appealing. I haven't had a chance to try it though.