My transition from Android to Windows Phone 8.1 made me appreciate the value of Microsoft Windows 8.1. The "modern UI" tile interface, which seemed ridiculous to me at first sight, became relevant after passing through the touch.
That is why I am following with interest the development of Windows 10. I am particularly excited about the GUI halfway between Windows 7 and Windows 8, the new Edge Browser (formerly Project Spartan) and the Windows Universal Apps, compatible for smartphone and PC.
The final version should be free for upgrade from Windows 7 and Windows 8, but it's not because it's free that you should not try before you install!
To download the ISO of the DVD to install the latest version Technical Preview is here:
It still has bugs, so install rather on a test machine or virtual machine. I used it on an old PC with core2duo, and it's still pretty responsive.