If you are getting the ThinkPad X220 or ThinkPad X230, and is wondering whether you should be getting the more expensive IPS Premium LCD, then this post should help you make up your mind (hopefully).
For those whom do not know what an IPS is, then have a read of the Wikipedia article here, and if you do not know what TN LCD is, then there is another Wikipedia article here that you can read to gain further understanding of these technologies. But in short one can summarise the IPS versus TN as having the following pros and cons:
To illustrate the wide viewing angle and off-angle colour shift effects of TN and IPS LCD in the ThinkPad X220 and ThinkPad X230, here are some of the comparison pictures that i took. Note: These monitors are at 100% brightness and have been calibrated by the Spyder4 Pro.
ThinkPad X220 IPS LCD Gamut (LP125WH2-SLB1)
ThinkPad X220 & X230 AUO TN LCD Gamut (B125XW01 V0) 93P5671