I currently have the VG278H... this is my second one. The first one I got would have that exact issue. But one time instead of getting mad and powering off my PC, I walked away for a couple minutes and when I came back it was on. Turned out that it took exactly 2 minutes to come out of standby.
I had to RMA the monitor for other reasons but my new one doesn't have that issue at all. Perhaps its the monitor?