I have the PB278Q. I use it for gaming (and lots of other things) and love it. I don't play FPS's, so YMMV on motion blur, but I have never noticed any. I have 2 computers hooked to this monitor. My new computer is built for gaming at 1440p while the older computer isn't quite up to that challenge so I run it at 1080p. The scaling is pretty good, at least one of the better ones I have ever seen. I've watched movies and played some games with the 1080p input and never thought the screen looked anything but beautiful.
I also looked at the MX279H when I was shopping for my monitor earlier this year. the lack of a VESA mount/non-adjustable base was the deal breaker for me.
I could not be happier having chosen the PB278Q and am now considering a second one!