I was using WD as well through the beta test period. Recently WD was downgraded by at least one rating agency. Since I installed Win 8 Pro on our laptops I have been using AVG 2013 AV free. It updates signatures on a schedule you select and has better heuristics than many of the other possibilities. Plus this does check all email as it arrives in my inbox. The Pro edition does even more.
I'm also using AVG free on both our Android phones.
I've wondered about WD falling behind and have noticed some articles mentioning it not testing as well lately. I also wonder how well it fare once Windows 8 becomes more widely used and hackers focus on that area. I quit using it on my Windows 7 install and went back to Avast, Comodo firewall and the free MBAM.