I installed Debian stretch and followed the instructions specifically with the exception of the modification needed for the Nvidia cards, as I am passing through an AMD GPU. The installation was straight forward on Debian and I am currently using virt-manager 1.4. I encountered no issues blacklisting the AMD card or installing virt-manager. I also did not need to install the ACS patch as my AMD card is in its own IOMMU group, however I am still encountering some problems with the VM.
I was forced to use win 8.1 instead, as I was having the same problems when trying to use win7 and win10 as I was on Kubuntu. Win7 just gets stuck on the starting windows screen and win10 crashes randomly until it gets stuck in a crash cycle.
Win8.1 seems to be more stable in the VM and did not seem to be crashing like win10. Once the win8.1 VM booted, the display came through the AMD GPU meaning that the pci-passthrough was successful.
Once the windows installation was completed, I only had to install the Ethernet and PCI drivers from the virtIO CD. Strangely under the display adapter section of the device manager, it just displayed Microsoft Basic Display Adapter with no exclamation or error.
I still went ahead and tried to install the AMD driver. During the installation process, the screen went blank and I lost video signal from the AMD card completely. Looking at virt-manager I saw that the VM was still running but the load usage had dropped to almost none. I tried forcing it off then on again.
What happens when you turn the VM on now, is that I get video display from the AMD GPU which shows the windows loading screen then it goes blank and I eventually lose video signal. At this point virt-manager still shows that the VM is running but with very low usage.
Also all this was done as root.