It works well, and is easy enough to attach.
Note however, that it can have quite an impact on the tone, as it completely mutes the afterlength of the C and A strings, and also changes the resonance frequency of the whole string/tailpiece assembly. Probably even more significant with a metal or carbon fiber tailpiece, which will normally ring quite audibly. That said, for scenarios where any of this really matters, one should probably be using a large diaphragm mic on a low stand anyway.