I mostly run Linux 'cos I hate Windows and can't afford a Mac, but I'd say from experience that any *nix (including MacOS) *does* require that a savvy user secure their own stuff, but do tend to make it fairly easy. There is still a balance to be maintained between security and usability. If I fully locked my system down, for example, I'd have to enter my root password every time I put a DVD into the drive or connected any other sort of external media. Since I have YaST, locking things down is pretty easy. Still, my HIDS does send out false positives, since I sometimes (often) forget to update the database when I do system updates. I also have to be careful when installing things that aren't in the official repos (just installing the package and not adding the repo). Also, the problems with Flash and such are indeed cross-platform. I don't allow Flash on any of my systems for that reason, and since mobile is killing it off, it's no real loss.
That said, I've had a couple of friends make the switch due to viruses, and have had no complaint (especially 'cos Netflix doesn't require Pipelight any more). Then again, they don't use M$ office and do all their gaming on consoles.