I have used this bit temporarily if I need to get the horse's attention in a few schoolings. I switched back to a "smooth" bit, but they are great tools when used correctly IMO.
It also depends on the twist and the "sharpness" of the twist, they can be very differently. The one I use gets attention, but I don't think it works off of pain.
Every great dream begins with a dreamer. Always remember, you have within you the strength, the patience, and the passion to reach for the stars to change the world. ~Harriet Tubman