I went from the guy saying "Ultrawide is a gimmick, useless" to becoming a true believer.... Likewise with curved screens, though I don't think I would care for curved screens on anything that was under 32-34" - large ultrawide + curve = happiness.
FPS games, I definitely appreciate the wider FOV. Even some of the simple games, such as Don't Starve, take advantage of it, not just stretching the graphics wider, but actually making more horizontal view of the landscape visible.
I strongly recommend it.
As for high refresh rates, I'm the wrong person to ask, as I play most things around 60Hz, and I can't really tell the difference from 75Hz and higher. One guy I know who says he can really make out the higher refresh rates and is pretty gung ho about it admits that he sometimes thinks when he caps the screen at 100Hz vs 144Hz, he can't tell the difference, but he does notice it when he dips to rates below 100.