Why, simple, because I can 😉 More seriously, I like to see what it is going to be. (the same I’ve done with Vista, 7 and 8)
To be honest, I don’t like the gui, same crap as 8. So I installed ClassicShell with Windows 7 menu, and that looks and works a lot better.
Except the standard menu it’s looks good. More important, it even works good.
The downsides :
It needs a lot more memory then Windows 7
Still no support for Linux filesystems
Update 22 may, 2015 :
At the moment I’m running build 10122.
It still works good in VirtualBox, but I’m not going to “upgrade” my Windows 7 for free to Windows 10.
All I have to do with Windows (and that’s not much 😉 ) I can do with Windows 7.
If necessary I’ll check out Windows again in 2019 (Windows 7 support ends january 2020)