I have tested this product and I can say that it is of good quality if used correctly. I think it is important to understand its operation, as a piezoelectric element, and combine it with a DI or preamp suitable for the type of signal it generates. I have tested it together with a Radial StageBug DI for piezo (Radial SB4), and the truth is that I am happy with the sound obtained. In the same way I also think that it is necessary to pair it with a clean amplifier of the Spanish/acoustic guitar type, and not with one for electric guitar. It can also work very well through the soundboard and PA.
What I noticed immediately is that the sound is of good quality (within the scope of piezoelectric sensors), but that it is not tonally balanced, that is, it emphasizes the low frequencies quite a lot. For this reason, a DI with a High-Pass filter, like the one I have detailed above, or some type of control over the equalization, either in the soundboard or in pedal format, is useful.
I would only change the cable, which seems to me to be of average quality, and a bit too thick. But I think it is adequate considering the price of the product.
Don't hesitate to try it if you want a non-intrusive solution for your guitar.