I've gotten ~10 hours from mine in real world use without putting any serious effort into getting the most run time out of it. I think it is officially rated for 13-14 hours and I''ve seen a couple of reviewers manage close to that so I think it's fair to say the x220 has roughly double the battery life of the MBP 13.
Dang, that is significant. I see people write 'significant' and I find that a lot of the time they mean something like 30-60 minutes or something. But double... that's no joke. The 9 hours on the 9 cell would be a significant step up as well.
If all a person wants is Windows, then that is a tough thing to beat. 12" is about as large a screen as I would want with 1366*768 display. With the IPS that is definitely a plus.
