When I was researching about contact pick ups I found this one to be accessible enough for the basics of a contact mic but without expecting much from it.
After several trials in different acoustic instrument I have to say that the sound quality is around OK but don't expect a great quality, specially because I tried to record a guitar and the was almost nothing sounding, it took me to level up the gain as much as possible to capture some decent sound, the bad thing here is the increase of noise you get when recording with so much gain, so in that sense is not the best experience and result.
I also did some experiments with this pick up attaching it to small percussion instruments and tried to get some samples and it was ok but nothing too clean, for more experimental things can be fun to use because of the noisy background you can get and if you are the type of user who likes to improvise.
I would say that to amplify acoustic instruments for a simple live session can be handy but nothing too elaborate, if you want also to do some experimental recordings (surfaces, unusual sound sources, etc) can be also handy without much expectations.