I've tried the xl2420t, and the colors are absolutely horrible, this is coming from a person who is used to s27a750d, which is known to have one of the best color profiles out there, if not the best on a tn monitor.

xl2420t is excelent in everything else, the response time is probably one of the lowest out there and the stand is absolutely fenomenal, but I just could not stand the terrible color quality, the colors are completely washed out, and in many situations blue would look like green, it's the most rubbish quality ive ever seen on a lcd monitor.

if you want low response time the best monitor is the lg w2363d-pf, and it will probably have better picture quality than xl2420 as well as lower input lag.

if you want mediocre input lag and great picture quality, Id say go with a samsung, s23a700d / s23a750 / s27a750d.

Hope this helps your decision making.