I've ran WoW on one of those since the spring. Works great, computer just thinks you have one huge monitor connected.

When I started multi boxing I ended up not using it, instead have my 2nd computer run 2 wows on the left monitor, then my gaming computer (in horizontal span) runs the main instance on my middle monitor and 2 more wows on the right monitor.

Hopefully you have a video card with lots of ram though, I have the 8880GTS 512mb, and even it would slow down sometimes when running one wow at 3840x1024. Bought mine before they had the DVI one, and sometimes when in Windows, text would get a little wavy. Never noticed the effect when inside the game though.