I'd stick with a 16:9 or 16:10 panel. I'd be worried that a monitor this wide would make playing FPS with a limited field of view a little strange.
That panel actually has a smaller area than a 27in panel. I also noticed that it has a 14ms response time which is rather high.
This. I use a 16:10 30" panel, and I could get by with 16:9 (I hate using that on a desktop) for gaming. Wider is actually better when the games support it, but as mentioned above, game developers (more so publishers) are lazy, and stuff gets left broken. So I wouldn't go any wider than 16:9 like a TV, since that's now the standard for gaming.
Also remember that panels get smaller per diagonal unit of measure with wider aspect ratios. A 27" 16:9 (1080p/1440p) is a physically smaller screen than a 27" 16:10 1200p screen. 21:9 is real bad; they're almost cheating listing it like they are.