The vast majority of the world's RAM is made by Samsung, SK Hynix (Hyundai Electronics), and Micron (whose retail brand name is Crucial).
https://www.statista.com/statistics/233419/global-market-share-of-dram-suppliers/
All the other RAM brand names like Kingston, Corsair, G.Skill, etc. simply buys DRAM modules from one of these three companies, and packages them into DIMMs for sale. They will frequently change suppliers too depending on who has the lowest price that week. That's why it's recommended to buy a 2x4GB pair, instead of one 4GB stick, then add another 4GB stick at a later date. Even if you buy the exact same model from the exact same brand, they may be using different DRAM modules and might not work together.
So aside from capacity, speed, and timings, you can pretty much ignore who the brand name is. Just make sure they have a lifetime warranty, and other users report their warranty service is prompt and trouble-free.
If you want to buy the US brand, then Micron/Crucial is your choice.
Edit: Also, 4x2GB = four sticks of 2GB DIMMs. 2x4GB = two sticks of 4GB DIMMs.