I don't consider myself a power user by any stretch of my imagination, I like things to work and even when windows xp came out, for most of my daily requirements, I was a happy Ubuntu user. Having said that, and ducking the usual oh oh, here we go, no doubt a windows flamer, I like playing my computer games and yes they require windows but for all other things such as surfing the net and checking my email as well as playing music I preferred Ubuntu.
When I bought my last computer, it came preloaded with Windows 7 and once I uninstalled all the trial this and trial that, I thought hmmm, this isn't too bad. (I can hear all the people who swear by XP groaning now) For my antivirus I switched to MSE as it seemed to work as well as any commercial product on the market including the free one provided with this computer as it was nearing expiry anyways. When I installed Windows 8 consumers preview I did so as I had messed up my libraries to the point of where my backups wouldn't run without error this and can't find that and it was either reinstall Windows 7 or jump into the deep end and install WIndows 8. (Yes, sorry; it looks like I am writing a book)
Imagine my surprise when it said that MSE is not compatible with 8. OK, no biggy, I let 8 do its thing and it installed. I checked the status of my computers security after it was installed and was surprised to see that an antivirus was in place and actively protecting my computer. I imagine that most users are not even going to install 8 until it becomes a commercial product and they either buy it and have their tech install it or they buy it already installed on their computer so worrying about whether MSE or defender is installed is not going to matter much to these people. The point is, it seems like a small issue, its like saying I bought an apple tree and the flowers are yellow instead of pink. (oops was that a Mac pun? Sowwy)