As a happy Linux user at work, I have indeed tried it out, and it seems to be good. I enjoyed using it, its Linux based, and I like Linux, but I've always used Windows at home.
Some games just do not work on Linux, and that absolutely kills it for me. If any of my games do not work on SteamOS, it just killed it for me. Take World of Warcraft for instance. I do not play it so actively anymore, but I've got an account and I can see myself going back to it someday, the fact that it has 0 Linux support makes me happy to stay with my easy to use Windows setup.
I used it for 2 days on and off when it first came out, just to test it, before I went back to my main OS drive.
I've got no big issues with Windows, so I saw no issue to totally move over.