Our 120 Hz model is the 2012 model, it's not for sale anymore ... the 144 Mhz is the current model.
Again, to my eyes, there is simply no comparison
in gaming between the 144 Hz TN monitors and anything else I have ever seen. Accurate color rending is important when doing photo editing.... you don't want grandmas cheeks in her glamor shots looking overly red so that she looks like she's a madam in an ole western bordello. That's why we bought an IPS monitor
OTOH, gaming is artwork.... will it affect your gameplay experience if superman's costume is cornflower or lavender ? The 144 Hz TN has better response time, better contrast, better brightness, better under low light conditions,smoother edges, does 3D and fully supports Lightboost / G-Sync. That's why the IPS system goes unused when 2 people are gaming .... last one in gets the IPS.
IPS excels in better viewing angles.... so if you game with 2 people sitting on either side of you the outside folks may not have as good a view. The IPS has better color accuracy....not sharper color, not brighter color, not deeper colors but they will show you more accurate screen colors, with one big caveat. If you haven't calibrated the screen, you wasting ya money on IPS. This will explain why
http://www.tomshardware.com/reviews/overlord-tempest-x270oc-monitor,3879-3.html
If you want to understand why 144 Hz TN excels in gaming, read this review.
http://www.tftcentral.co.uk/reviews/asus_rog_swift_pg278q.htm
many peeps still prefer IPS over TN, we all ain't "built" the same.... Best thing for you to do is go out and look at some panels and read some reviews.