You can do it now, I stuck it on a couple of days back just to be nosy, still got it on now.
My problem is that I am looking at updating my computer in the next few months, going for a Ryzen and by all accounts MS will not support windows 8.1 or 7 on the new processors, so I may not have any choice but to go to Windows 10.
so I will have a look and see how much of the spying stuff i can knock out.
I will go back to windows 8.1 in the week until I update.
Anyway, there is nothing really to get excited about, the 3D paint is just a gimmick, it is a bit of fun for a while. The start menu is more or less the same, you can now have folders on the start menu tile section, so if you like the start menu that is pretty good, so say you can have all your music software in one place. there is the new gaming section that is suppose to put all resources to games, but i only play a few games and have not tried it out.
Cortana is even more in your face, but easy enough to shut up but still running int he background, which is one thing that will go again.
You can use Cortana to set up windows 10 on installing, but only from a clean install, I had a muck around with it as i done a clean install, but I had to slipstream my sound card drivers in to the ISO. I am amazed it worked, I thought Windows 10 would have knocked them straight out.
The cortana set up is not that great, you still have to partition the drive as normal by hand and it is only stuff like setting up an account and allowing cortana permission to use your data that uses voice commands.
More rubbish is installed, that is not needed and yet again, lots of apps that can not be uninstalled by normal means.
Oh yes the telemetry is now basic or full, no in between and still no, I do not want MS spying on me option.
That is it really.
Plenty of videos on you tube about it if you want a look, like here.
Desktop machine now powered by windows 8.1 pro 64bit, no dreaded metro, laptop by Linux