@Stux we have two Optane systems setup in the lab. Personally, I think it is the best ZIL/ SLOG device around, however, you are going to run into other limitations quickly. For example, you really need a 40Gbps or faster fabric. Running FreeNAS is not optimal at those speeds. Great drive, but if you are not at the higher-end of the spectrum, just get a P3700. It was one of those projects that we realized that the P4800X was best suited to a higher-end demographic so we setup systems in DemoEval to let folks run their own workloads.
The two drives we have have been transitioned to NVMeoF based solutions e.g.
Trends for Flash Memory Summit 2017 - ServeTheHome where we showed our 70/30 mixed workload as shown at ISC17 in Germany this year.
Availability is rough still. The large players are consuming so much of the supply that even adoption by major storage vendors seems to be slowed by supply concerns.