I've returned two 1440p monitors as they didn't really excite me, even coming from 1680x1050. I've got a 4k screen coming in the hope that it'll be what I'm hoping for. This is on an MSI Gaming 980ti as well, which was eating every game I have on full settings.
It won't be enough for 4k alone. Did you get G-sync? 'cause to be quite frank you'll need it at 4k. Frame drops can be really sudden and really harsh.