Not as good a sound as I'd hoped
It's a cool concept. And having a pickup you can put on and take off: great. Based on what I'd heard in videos, I expected this thing to sound good as well. Unfortunately, it sounded just like any other piezo transducer. It also dampens your acoustic tone a great deal. Not a big problem in many cases if you're amplifying anyway, but if you'd be planning to use this in combination with a mic or you really want your fiddle to sound good under your ear, this isn't the product for you.
With this thing fastened on the f-hole, I was a little worried that an accidental tug on the pickup could result in substantial damage, I'm not sure if this is the case though. The thing is very well built though, and I'd read some people were worried the clip mechanism could damage your finish, that's not something I'd be worried about. It has no sharp edges.
Easy to put on and take off
ConsSounds like any other piezo pickup