That's pretty strange, I made the exact same decision last week. I decided on the PB278Q because in reality, 1440p is the only way to stress my 2 780Ti's. I have to say the color accuracy is tremendous, its totally worth having 2.5x more pixels than 1080p is you want the premium gaming experience. My 2 780Ti's keep me around 75-80 FPS even on Crysis 3 high settings. With so much GPU horsepower it's pretty much a no-brainer for me.
What sealed the deal for me is G-SYNC. G-SYNC will be available soon on 1440p monitors. I saw the attraction in the "high refresh" "low latency" but in reality G-SYNC solves a lot of those problems. Also the PB278Q is a PLS panel, compared to a Cheapy TN panel.
If you are running SLI, then you should take advantage of the beauty of [IPS] 1440p monitors with their large screen size and awesome resolution. You will also get spoiled by 1440 resolution with all of the real estate you have for just everyday apps and etc.. Also Benq uses a TN panel which has poor color accuracy and viewing angles giving you a less immersive experience. I currently use the Yamakasi Catleap Q270 1440p monitor and love it. G-Sync is something that I'm certainly excited for as well, but it will be a while before the consumer market will this because it will be pricey. Hope this helped.