In 2009 and 2008, NSS Labs did very similar reports with very similar results. They were paid for by Microsoft. I don't know whether this one was also paid for

In 2009 and 2008, NSS Labs did very similar reports with very similar results. They were paid for by Microsoft. I don't know whether this one was also paid for by Microsoft (it doesn't seem to say anywhere in its text, though I didn't look very hard). Obviously there's reason to be a bit more skeptical about a paid-for study than a truly independent one.