It is wonderfully loud. I can change it tones and loudness by covering the tongue opening by hand, cloth or even using the core tube from paper towel, which you cannot achieve with the V-shape version.
For better control, I would NOT swing it in the air, but instead hold the handle vertically (by hand or with a clamp) and turn the body clockwise with my right index finger. In this way, you can generate a very smooth continuous rattling. Beware of splinters though - can put on a sticky tape at the edge of the opening. Hope you like it too.