I think the grandparent was right. MS now is hugely better than the MS of 10-15 years ago. I'm not going to try and objectively prove that as I don't care enough about MS and probably couldn't anyway.
But the NT4 to XP/2003 era was appalling security wise - but they changed that. IIS went from swiss cheese to one of the tougher web servers to break. You just don't hear any more about the kinds of problems they used to have. If you endured those days or just laughed from the sidelines, you don't need any hard data to see that they have improved a lot.
I found this paper from Theo de Raadt illuminating though. He steps through 10+ years of OS hardening techniques OpenBSD has put in place to prevent badly written applications misbehaving. Towards the end he summarises how other platforms do this stuff - the only other platform that did it all by default was Windows (yikes!).