You state that you have been able too boot from your non-apple nvme driver in your mpr2015 which is awesome news. But I am a bit confused because you also say that the Sintech's adapter is faulty. With which adapter did you manage to boot from the non-apple nvme drive?
You're right and there is no longer any doubt that firmware of my MbP 2015 has been updated with High Sierra Beta 9.
I tried with an anterior beta version of HS and I was not able to boot on my NVMe disk... Until the beta 9.
I can assure you that NVMe is now bootable on this machine.
However, please remember that it can be removed on the GM release...
You're right but all of this is a matter of price... More that 350$ for 256Gb with SSUBX Samsung where it is so easy to grab a Samsung 960 EVO 256Gb for more than half the price.
Plus, it is a HUGE improvements for 2013/2014/2015 MbP/MbA users to be able to replace SSD by the new NVMe standard.
I'm waiting the delivery of a CHENYANG adapter to see if it's the Sintech's one which is faulty
I'll keep you all in touch.