It's 27" and also an IPS panel so better color and viewing angels. (it's "only" 4ms but that's really not a big deal and the blur/ghosting is insignificant at this refresh rate).
Fastest and best are NOT the same thing. The lower response time helps eliminate blur/ghosting however 4ms on a 144Hz monitor has very little blur (less than on a 60Hz monitor). see blurblusters site if confused
The picture QUALITY (in general and viewing angle) is better on IPS ( the 4ms screen).
So sure, a TN panel is 1ms but it's NOT the best screen overall so suit yourself.