The basic design of a melodica is pretty simple, but there are very significant differences in sound, in the nuances of design, and in quality of construction. They are not all made in China. Even in Asia alone, they are manufactured in Japan, Indonesia, and Korea (at least) in addition to China. Those manufactured in Japan, the Yamahas and upper end Suzukis, are very clearly superior in construction; I say this on the basis of having disassembled a lot of different melodicas. The reeds are more stable on those Japan-made melodicas; it’s obvious if you tune them. It’s much easier to get consistent intonation readings, and they hold their tuning better. Their reeds are also noticeably less susceptible to corrosion. Others can speak about the older or current melodicas made in Germany and Italy. So, while it is true that there are some Chinese melodica manufacturers whose products appear under different brand names and at varying prices for the same or very similar instruments, there’s quite a bit of agreement as to the superiority of Hammond (Suzuki), Yamaha, upper end Suzuki, older Hohners, and some others. Also, read the reviews here and see what the professional musicians have to say (Melodica-Me, Lowboy, Troy, and others).