Let me start by saying that I believe all piezzos are bad.
My old full circle was giving me some problems so I just bought this one for a fast replacement.
Although it is quick and easy to install I needed a reset on my bridge because it was not making a perfect contact with the pickup so it rattle in some notes causing a very nasty noise when amplified, similar to an electronic distortion.
Once sorted, what a beautiful sound, couldn't be much happier, it is much close to the real sound of my bass than the full circle as ever been.
What more can I ask, it's "cheap", easy to install and remove whenever you want and with a great sound.