Automobilista. Messing about with Nvidia view etc to get triple screen to work is a bit of a pain, especially when reverting back to Desktop after finishing gaming - You have to mess about getting your screens back to normal.
However, playing Automobilista on a triple screen set up is a revelation! The wider field of vision makes a huge difference from an immersion perspective, I find myself driving more naturally - you can anticipate what the car is going to do. Whereas before (when using a single screen) I was usually playing catch up (crashing). For comparisons sake, I own a 34" ultrawide and to be fair, I now prefer triple screens for driving especially as the monitor borders are barely noticeable in game.
Although I would say that FPS play better on a single ultrawide.