Your post was bound to get a few rises here, PLF. Check out the following thread, in which I compared the Yamaha P-37D to an identical looking inexpensive clone. I thought at the time that both might have been produced by the same manufacturer, but that their sound was completely different, and the materials and workmanship of the Song Lin were grossly inferior, as is the sound.
Now, after doing research on the history of Yamaha Pianicas, I do not believe that the Song Lin is produced in the same manufacturing plant or that Yamaha would have any business dealings with a company that would produce a melodica of such inferior quality. Yamaha has been very conservative and has closely guarded the quality of their Pianicas. When Yamaha exported production to Indonesia (where all their Pianicas are now made), there was no drop-off in quality. Close comparison of a current P-32D (made in Indonesia) with an earlier P-32D (made in Japan) shows this. All the parts are identical, same material, same finish work, no detectable difference in the reeds, and the sound is the same. The Song Lin is probably made in China. It is a cheap imitation, a counterfeit. Genuine Yamaha Pianicas bear the Yamaha label. During the 1960s, Yamaha Pianicas were manufactured by Tokai Gakki, and some (same models) were marketed by Tokai Gakki marked simply with “Pianica.” Tokai Gakki still makes some pianicas, but not models that are the same as current Yamaha Pianicas.
There are lots of melodicas that look a lot like Yamahas, because the modern generic Chinese melodica is heavily influenced by the Yamaha look.
The Yamaha look-alike to which you linked might be a nice melodica and a real bargain for what it is. But it won’t be the same thing as a Yamaha P-37D.