> I have just built a PC with a M.2 Samsung 950 Pro on a Z170 motherboard

Ditto - I built mine at the beginning of the year. It's very fast, but I learned two things that weren't widely reported at the time.

1) The chips on the drive get _very_ hot under use (thermal throttling kicks in at 75C). Even with minimal use they seem to have a running temp > 50C. I'm a little nervous about the long-term reliability of the drive based on the heat alone.

2) Boot speed with Windows is still fairly slow unless the drive is formatted to GPT (GUID Partitiion Table) instead of the default MBR. It's possible to do this when installing Windows, but there's no easy way to convert after installing