Well whatever floats your boat, though getting above 120FPS on a 780 might be a challenge even at 1080p on BF4 mostly because those games are so demending in the upwards of beyond 75hz. My monitors do refresh at 75hz as well so I have my Dynamic V-Sync capped there and for me it stays smooth as silk on BF4. I prefer gaming at higher resolution in the long run because higher FPS gains I see minimal differences even in a game like BF3/4, I have a friend with NVidia 3D and a 3D monitor that runs at 120hz and even playing BF3 on it, the difference between my 75hz setup was so miniscule that I personally saw no point.Well I'm lucky enough I don't have to pay quite so much for the monitor, so I'm happy to get one, and the 780Ti will boost performance sure, but not night and day levels, playing BF4 on a 1440p monitor and a 1080p monitor is (almost) night and day difference on a non overclocked 780. Hell I probably won't bother with the 780Ti if this screen does come in as the 780 is almost overkill at 1080p.
In games I can notice the difference relatively clearly between 60Hz and 75Hz, this is because my 75Hz monitor is only 1280x1024 so I can keep 75fps in pretty much anything I throw at it, I use this screen more often than I should because it is just soo smooth, This is why I want this G-Sync monitor, because I want that smoothness at a higher resolution.
I think G-SYNC can be nice, but the fact that I would have to replce all three monitors and pay at least 1500 bucks to make the same setup would about kill me let alone having to buy at least 2 780ti's to keep up with that type of setup (Since HD 6990's cant use G-SYNC ). If mantle comes out and gives me a 20% boost in performance on BF4 like its claiming, then theres not going to be a second thought and ill grab some 290X cards. Otherwise, im grabbing those 780ti Dual 8pin cards (When they come out) and running NVidia surround, though I doubt even then ill grab a Gsync monitor until I can get one for 300.