Mine has an IPS panel. It looks great from any angle, but it suffers from a mild ghosting effect when some colours are displayed [1] [2], mostly dark-blue colours. I didn't notice it for the first time until I upgraded to Windows 8, which uses this colour on the lock screen [3]. I have no idea whether this problem is fixed in Lenovo's newer IPS displays, but I find it barely noticeable and rarely a problem.

[1]: http://forums.lenovo.com/t5/X-Series-ThinkPad-Laptops/Faint-...

[2]: https://www.pcworld.com/article/237105/article.html

[3]: http://techtogeekz.com/wp-content/uploads/2012/03/windows_8_...

I too have an X220 with the "HD" screen. It looks great. The only issue is the awful resolution, but it's the same with the regular panel.

I should probably mention that it runs Arch Linux without issue.

I've got one of these, with the IPS panel. It is fantastic. I find it better than my MBP, to be honest.

The X220 IPS panel is highly prone to developing pressure marks, even when babied. Also, it's low resolution (same as the TN panel).

I would not recommend it.