Its fine for piping out to 2 24" monitors. The BE is an overclocked version of the gtx260. Also its not a big premium, its about $250 right now. Its pretty awesome, its in my personal/work rig right now. It ranks up with stock GTX280s for cheaper.
I think it should be fine. I don't multibox WoW, but I do do it for EVE and I run VMware. Not sure how those stack up to multiboxing WoW but I think its close.