The question is hard to answer given the information gaming. If you asked me which was the best hand tool hammer, screwdriver or wrench ? ... the answer would depend on whether you wanted to bang in a nail, put in a crown or remove a bolt. At the very least resolution and usage is required.
If we are talking PC Gaming the best image quality comes from the Acer XB271 HU and the Asus PG279Q. Both are IPS, 165 hz with extremely low response times (5-ish) and lag times (3 ish) and have G-Sync and ULMB capability ... bear in mind that there are real measured response times not the fake numbers on manufacturer spec sheets.
G-Sync is ideal between 30 fps (Freesync from 40 fps) and 70 or so ... after 70, you may want to switch to ULMB...