I'll say just one thing about Windows 10 since I'm not using it and barely supporting it. My wife has been on the Win10 preview since late May and she's been mostly happy with it until the last couple weeks (when it started crashing for no apparent reason). Yesterday she upgraded from the last preview to the first release and her performance took a very noticeable nosedive. I don't know what Microsoft did between the final preview and the first release, but it was clearly something wrong.