I don't want to sound patronising but have you checked your graphics card supports the slightly freaky 2560 x1080 resolution? It'd be a shame if it didn't support that width. The dual link looks cool but I can't help feel you'd be better off with two 16:9s and you can angle them slightly inward for added comfort.
If you go for it, it'd be cool to hear how you get on with it.
Edit: I just checked the native resolution on my 27" iMac (no clever retina scaling). It is 2560x1440 which is obviously a more conventional aspect ratio. I find that a bit small for things like menu and toolbar text, so I actually pull the resolution back to 1920x1080 for normal use, the 1080 height is just about perfect for me working at a distance where I can see the whole screen comfortably without hunting around it with my eyes. This works well for having two documents open wide by side at readable viewing %. I can see the attraction now of having and extra 640 pixels width of the LG, but I don't think it would allow you to squeeze a third document alongside at a sensible viewing %.
I also just saw how good value these monitors are compared to buying two decent 23" displays.
5k display 27" iMac not under consideration?