There are four companies that share the same product list and manufacturer: HYT, YD Peptide, Annie, and WHT.
From what I’ve seen, the main advantage of YD Peptide is customer service they usually reply quickly and consistently but their prices are higher compared to HYT, for example.
Based on experience, the factory they usually produce with is generally decent, but there have been cases. For instance, regarding HYT, one user sent HGH for testing and the results were very poor.
I’m not saying this happens every time, but as we all know, when dealing with Chinese sources, product quality is never 100% guaranteed.