The problem with the Acer IPS is it doesn't support 3D Vision, 4ms is still to slow for it to work properly I think. The nvidia drivers won't detect it as a compatible monitor, so you can't even try it :/
I have an Asus ROG Swift which I bought recently. There are 2 main issues with the screen. First it has very faint vertical lines trailing moving objects caused by pixel inversion (you might not notice this as other monitors do it too and you might just be used to it). Second is the viewing angle issue you get on ALL TN screens, being 27" you notice it a lot more, especially on the desktop.
Considering I'm blind in one eye, 3D anything has never appealed to me. And I can't speak as to why it doesn't support it, but from the reviews I've read, the XB270HU actually has lower latency and input lag than most 1ms monitors.
http://www.tftcentral.co.uk/reviews/acer_xb270hu.htm