Just updated my Mac Pro 5,1 to the new windows 10 build 1511. It showed up in windows update yesterday, but was a huge download. It turns out its a complete reinstall of the OS. I used the microsoft disk maker app to download a fresh .iso from their site and make a install dvd. The new setup has win10 normal and pro, on one disk, it seems to choose which to install based on your license key, or previous version.
The install went smoothly, I put the dvd in, started the installer while booted into win10, and it went from there. No problems, device manager is good, and bootcamp control panel seems fine. New rules for the version 1511 of win10 is you can install it using any valid key from win7/8/8.1. No more required upgrade on the old OS, then activate, then format and reinstall. Now you can do it clean from the start, just use your existing key.
Once you complete an upgrade from older versions, it creates what they call a "digital entitlement" license. No key is needed again on that system, as the MS registration servers track your comp based on hardware ID, probably cpu and motherboard serial numbers. So, you install it, skip the windows where it asks for a key, once online, it checks the servers and your activated.
Nice improvements, good job Microsoft.
One disk for normal or pro, and easy clean installs using previous OS keys.