Or as I call it
You never had a choice. All those poor poor people using 7, or 8 are just deluding themselves, sooner or later they will join the Win10 collective and just get charged a subscription fee instead. Monthly. On their credit card.
You really think that all those patches are OS fixes? No, they are sneakily downloading 10 a bit at a time, all that mysterious drive activity is just the BORG slowly assimilating your system via "free" wifi and PC interlink nodes on USB slack space, Bluetooth, phone data, unused space on burned DVDRs etc. One day soon you will wake up and find 10 on your system. Hahahahaha. (sound of millions of PCs screaming in horror)