Summary: For the cheap price, this is a perfect entry into acoustic pickups for those who have none. High build quality and clean sound, though lacking in separation and dynamic range from only having a single coil.
I bought this pickup for an old concertina acoustic guitar bought in America sometime in the late 80's. The fitment of the pickup into the soundhole was very good, and the cork cushions protected the guitar from the pressure. I would prefer for there to be some way of taking the cable back out of the sound hole more easily, perhaps a weighted, formed upside down V shape would keep it in place (or a way to fix it to the side of the pickup). I frequently found that I was hitting the cable with my plectrum while playing, or having to play closer to the bridge (and further from the pickup) than I normally would just to avoid the wire. This is a potential area of improvement, but for the cheap price its acceptable. However, if you're buying a pickup for the first time and getting a more expensive one, pay attention to how the cable sits/is fixed coming out of the soundhole. As I didn't want to drill a hole anywhere in my guitar for this and its a temporary device, this perhaps will not be a concern for everyone. The build quality is excellent.
Sound: The sound of the pickup is very decent for an entry level pickup. Considering that I had no way of in-line recording before buying this, if you want the cheapest way to get in-line recording from an acoustic guitar you really can't go wrong here. However, an extra €50 on a pickup with more coils is a worthy consideration if you're going to do a lot of recording. I find the sound warm, and well-centred over all, but lacking separation between bass and treble. Other reviewers may offer better expertise, but to my amateur ear I put this down to the single coil. Of course, the result is there are no dials for bass/treble/volume and it is not an active pickup, requiring amplification. I use plug the pickup into the back of my Samson G track pro and record in audacity.
Very happy with this purchase as a first pickup and its given me a lot to think about before dropping money on more expensive pickups.