I'm not detesting that it's not the best AV out there... But as long as you're not an avid pornaholic or frequent of sites that introduce various baddies to your PC, it works fine.
I've been using MSE for several years now and I've not been infected, but I do have to deal with infections on an almost daily basis (I'm the IT Coordinator for an architecture firm of about 80 employees) and know what to look out for and how to keep from getting infected.
I've got access to other security suites such as Vipre AV, Norton, and McAffe, but I've tried them all and they all just use too many resources for my likings. Back when I had a crap-puter I was clawing for all the resources I could get just to play BF and I found that MSE offered the lowest footprint and least-invasive AV protection.
I wouldn't install it on a known offenders computer, but it's not as bad as that article makes it out to be.
Again, not trying to argue, just giving my two cents regarding MSE as AV... Sorry for jacking the thread... I'll leave now.
-Gvnr