Beware of the refresh rates at different resolution settings. I have been using the ASUS PB287Q for about 2 years, as a computer monitor, and when I connected it just recently to an XBox One X I realized that the monitor doesn't support 4K at more than 30Hz through HDMI, it only supports 4K at 60Hz via DisplayPort. Therefore I cannot use the XBox at its full potential. The ASUS has a TN panel, with 1ms response time, but won't support 4K at 60Hz unless you can connect through DisplayPort.The Asus monitor has been out for 4years. The BenQ is new this year. And the BenQ comes with FreeSync which is good if you had AMD gpu. However, I'd lean towards the Asus cuz I have owned two of theirs and been happy. And the only reviewer I've found that has reviewed both monitors, PCmag, gave a higher score to the Asus.
OP didn't mention anything about using an Xbox with the monitor, so that doesn't add to the discussion. But yes you need DisplayPort to get the highest resolution and Hz out of your monitor, I have DP connected to my Asus monitor.Beware of the refresh rates at different resolution settings. I have been using the ASUS PB287Q for about 2 years, as a computer monitor, and when I connected it just recently to an XBox One X I realized that the monitor doesn't support 4K at more than 30Hz through HDMI, it only supports 4K at 60Hz via DisplayPort. Therefore I cannot use the XBox at its full potential. The ASUS has a TN panel, with 1ms response time, but won't support 4K at 60Hz unless you can connect through DisplayPort.
As a computer monitor for office work I think the ASUS is great, my computer doesn't even output more than 2560 x 1600. Even at 2560 x 1440 I can work on two side-by-side documents very comfortably. I do not need true color reproduction or anything like that for my work.
I happened to be researching the BenQ EL2870U lately, for the XBox, and that is how I found this 1-year old discussion. From the specs that I read the BenQ supports 4K @60Hz, plus has HDR and FreeSync. So for the price it looks like a good option for gaming.