Like sand through the hourglass....
PCI Express 4.0 SSDs were a certainty even before Phison shocked the world with the first PS5016-E16 announcement. We know other companies have designs in the works, but the E16 will be the first to market. Phison used a lot of engineering resources to make that happen, and it will be an essential milestone in the company's history.
We were not able to see the full power of the Phison E16 today but hope to write that article in the near future. AMD has yet to release processors and motherboards to media. We learned just before Computex that motherboards are in very high demand for engineering teams and limited in quantity.
We were able to show performance of the first E16 reference design in existing systems with existing PCI Express technology already in place. Shoppers will face the very likely scenario of buying a PCIe 4.0 capable SSD before investing in a motherboard with PCIe 4.0 support. Compared to other SSDs shipping today, the E16 on a PCIe 3.0 bus is a strong option that should remain high on your shopping list.
Pricing will be a significant factor for everyone. The first PCIe 4.0 SSDs will have a very long lifespan in terms of usability, but some may want to wait until they have accompanying PCIe 4.0 hardware to make full use of the drives.