Just to give you an idea - I have dual 260s - and I was pretty impressed with the 181.00
drivers.
Plus, the WDDM has one missing *main* feature - you cannot select which card to run SLI on as the main card. The 180.xx series and above you can.
Not very important, of course, for those not using SLI - but for those using it - it is important - especially in a dual monitor setup....