Ironically, we thought that Windows 7 would have had better support - but, as it turns out, for Circa 2H2015+ hardware, it's probably not a great platform. Here's hoping that Windows 10 stabilizes for a few years, and all the vendors agree to support that platform....
Use this guide http://forum.notebookreview.com/threads/guide-installing-win... It worked for me. Also this :) http://www.samsung.com/semiconductor/global/file/insight/201...
I have a windows 2008R2 box at home running on a 950pro.
Windows 7 doesn't have M.2 drivers by default. See http://www.tomshardware.com/answers/id-2817439/install-windo... and good luck! I believe Windows 10 is fine though.
With MBR the system would still take 30-60s to boot, but GPT reduced that to less than 10s.
You may need to copy the install data to a USB drive to get it to work. Initially I burned the iso image to a DVD and but then that DVD drive wasn't bootable under UEFI.