Intel P5800X user, checking in. The latency improvement when I switched from a Samsung 990 to the P5800X wasn't quite as mind-blowing or revelatory as the HDD to (SATA) SSD switch was ~16 years ago (OCZ Vertex LE -- $300 for 100 GB!) but compared to standard nvme it still feels like a dramatic improvement. It's startling to realize how much performance we're leaving on the table even with nvme ssds. Build times for what I work on dropped by much more than 50%, if I remember correctly, when I switched and everything on my system feels more responsive.

Edit: optane also shows what the SSD/nvme sequential-throughput marketing wars have cost us. Latency and random 4k iops always should have been the focus (in research, development, reviews, and benchmarks), not sequential throughput.