Despite another review site mentioning the S55s are now shipping with the Phison S10 controller (which, when included with up-to-date firmware and good MLC, can trade punches with upper-tier SSDs), the one I got in Feb 2016 still uses the S8 controller.
Cheap; MLC NAND based SSD for the price of a TLC SSD
Using older Phison S8 controller (same as Corsair LS and Patriot Blaze)