I used it for a few months in my server, mainly hosted virtual machines. I upgraded to the 1TB version of this PM951.   This is actually a very fast solid state drive. Definitely faster than what the spec claims, and much faster than the Intel 600p NVMe SSD.  What you see on the picture is the actual drive; benchmark was ran in the same computer; Has about 1k hours of uage.   No issue, works like new.

Specs:

Model: Samsung PM951 (MZVLV512HCJH)

Form Factor: M.2 2280

Interface: PCI Express Gen3 x4

Capacity: 512GB

Sequential Read: Up to 1,850MB/s

Random Read: Up to 250K IOPS

Sequential Write: Up to 590MB/s

Random Write: Up to 144K IOPS