Windows 10 runs great on my 1,1 after getting it to boot in AHCI mode. Before that it was a pain on HDD, with an SSD it probably wouldn't matter. For the initial W7 install I had to modify the .iso to be bootable. W10 installed hassle free on top of that. I then installed the original OEM drivers where possible (Intel for chipset/network, Realtek for audio, AMD for graphics).
Additional drivers were a different thing, to be honest I lost track of which and how many Bootcamp drivers I tried to install, mostly for Apple keyboard and Cinema Display (volume and brightness controls), and what method I used. It was a mix of pointing Hardware Manager to drivers, running single .msi normally or as administrator or using cmd.exe.
Wifi doesn't work with Apple drivers, I had to install some third party driver for an HP or Acer branded laptop. Bluetooth doesn't work with Apple's Magic Mouse, don't know if it works at all, I don't have other Bluetooth devices.
I use this for games only, I'm impressed with what this machine is still capable of with a R9 280X.
So quite a journey. Now that I think about it, maybe I'll do it again from scratch just for the fun of it and to streamline the process