I have the ASRock AB350 Pro4 motherboard. My boot drive is the Plextor - M8Pe NVMe SSD (256 GB).
There is a big difference between NVMe and Sata, but only for doing things that require reading the disk. If you're playing a game that is not disk-intensive, then you won't see a difference. But for booting, and general use of Windows, the NVMe drive is awesome.
Not all NVMe drives are equal. My Plextor is no match for a Samsung 960 Pro, but it was also a lot cheaper. I considered a Samsung 850 EVO, but read too many reviews about bad quality.
A Sata M.2 drive will get you ~500Mb/s. An NVMe M.2 drive will get you anywhere from 900-3,500 Mb/s.