These look like they might be cherry-picked OS releases. Let's see a comparison to every OS released over the past few years, not just carefully chosen flavors of Linux, OS X, etc. And since (AFAIK) those other OSes didn't have a limited businesses-only "pre-release" it'd probably be more fair to count the 90 days from the Vista release to the general public. If it holds up with those conditions, I might be impressed by Vista's security.