If you are going for snappy load times for games and Windows, then a good quality SATA III SSD is just as good as the fastest m.2 NVME drive. 
 
Knowing what I know now I'd have invested in a larger SATA III SSD over a faster NVME drive. I don't do database work, so the extra IOPS/MBPS performance that these NVME drives have is wasted (except my file transfers ARE much faster between my RAID array and NVME drive, which I don't do all that often).
 
However, the m.2 isn't a waste in that it is an extra drive slot available. And who knows - in a couple of years general purpose software programming might catch up and actually be able to use the raw speed available with m.2 NVME drives.

arestavo
If you are going for snappy load times for games and Windows, then a good quality SATA III SSD is just as good as the fastest m.2 NVME drive. 
 
Knowing what I know now I'd have invested in a larger SATA III SSD over a faster NVME drive. I don't do database work, so the extra IOPS/MBPS performance that these NVME drives have is wasted (except my file transfers ARE much faster between my RAID array and NVME drive, which I don't do all that often).
 
However, the m.2 isn't a waste in that it is an extra drive slot available. And who knows - in a couple of years general purpose software programming might catch up and actually be able to use the raw speed available with m.2 NVME drives.

I'm running 850's Evo's already, so the M.2 would purely be indulgence. It's not going to offer me any major speed increases from what your tests results are showing, and the price per GB ratio isn't the greatest either.  I may have to rethink this and live with not knowing if my M.2 is functional.
 
Thank you for all the information

I'm glad that you found that information useful!
 
There are occasionally some sales that make them just about the same cost as a SATA III SSD - Black Friday might have some good deals as well.