You mean an ultrawide, like 3440 x 1440? As someone with 3 x 1200P displays, if my primary use-case was gaming, I'd swap for a 1440P ultrawide any day of the week. Surround gaming (multi-monitor) is still only sporadically supported and getting it working often involves making some sacrifices (like poor HUD elements scaling/position, or frustrating menu issues) and/or spending time and energy researching and trying to apply fixes/hacks/workarounds. It's fantastic when it all works, but that's only sometimes and the hassles when it doesn't work can be really frustrating.
I absolutely love my 3 x 1200P displays when it comes to productivity (i.e. work). Each of mine swivel and I regularly work with 1 landscape and 2 portrait displays. I would suggest that if your primary use-case is work related, then 3x1080P displays would have an edge. But for gaming, there's no question in my mind that a single 1440P ultrawide, particularly a GSync one with 75hz+, would offer a far superior gaming experience in a much wider variety of games.