Consider good. Kingston do not manufacture their own NAND chips and DRAM. Crucial is actually Micron and they manufacture both NAND and DRAM themselves. Kingston bought chips from 3rd party and assemble it. You can imagine. If i manufacture my own chips , i would definitely keep the best chips from binning process for myself rather than sell to my competitor.

Somewhere back in 2014. Kingston was short of NAND chips for V300 model. Performance was very different if you get different batches because they use different NAND chips in tht model. So in order to fulfil market demand they simply buy their materials even subpar ones. Consumers fell cheated back then and tht case was widely known. Here
NAND manufacturers themselves that sell retail SSD will not hv such issue as stocks are always reserved for ownself as priority , got excess only sell to others.
So i would say, buy only Samsung , Crucial/Micron ,Sandisk/WD, Toshiba/OCZ , and Hynix. Dont buy from those dont manufacture their own NAND chips. You dont know what is " under the hood" as bill of materials can be different as they can buy from different supplier.