I am in the same boat except I want 120+Hz, so I'm waiting for a HDMI 2.1 display. I'm set on 32-40" as my ideal size. Do not want to step up to 48".
Also, I have the XB321HK and I would advise you to avoid it. It is a nice monitor with a glaring defect. Half of the screen randomly flickers for one or two frames every few minutes. There are posts on Acer's support forum and when I quit watching they had no fix nor did they admit to any problem with the panel. I have learned to live with it, but it is unacceptable on a $1200 (back when I got it) display.