I use this on my double bass for monitoring purposes, and sometimes a little blend to the front of house.
It isn't a true representation of the instrument, but it sounds less nasal and quacky than the three different piezo pickups I'e tried.
It sticks easily with the provided putty, never falls off, and sounds more than OK.
I use this in conjunction with a dpa 4099. The mic sounds amazing, but to avoid feedback and/or bleed from other instruments I like to have the little Oyster as well.