ANACOMDA is making a nice proposal with the Phison PS5018 E18 controller, paired with 1GB DDR4 2666MHz DRAM for caching, while the NAND is Toshiba 112L BiCS5 TLC (four packages). The performance matches mainstream to high-end drives, while providing optimal performance after writing about 1TB of data (a part of the pseudoSLC will empty itself when the drive is in IDLE, so the write speed will be able to recover).