At the core of the article is Apple’s choice to adopt the speedy PCIe SSD bus technology along with the NVM Express device interface.

By adopting the PCIe/NVMe standard, Apple has been able to deliver higher performance in terms of read/write speeds and latency when compared to traditional SATA-based PC designs.

And:

It’s not a surprise, Handy said, that Apple settled on PCIe, as the price for the controllers are already approaching those of SATA controllers.

“If they both cost the same, then why use SATA?” [industry analyst Jim] Handy said in an email reply to Computerworld.

Interesting.