Thanks to the new Phison PS5012-E12 NVMe controller, the upcoming Viper M.2 SSDs will be able to provide almost identical speeds for sequential reads and writes, and will come in capacities ranging from 240 GB to almost 2 TB.
https://www.notebookcheck.net/Patriot-demos-Viper-M-2-NVMe-SSDs-with-impressive-read-write-speeds.281936.0.html