"American Rifleman", one of the NRA's publications did a review on many 12 ga slugs and sabbots for smoothbore and rifled barrells. One of the ones they did was the truball. They gave it a good review. Although they always give stuff great reviews (can't make the advertisors unhappy now can we?) they did post results shot from 3 shotguns if I remember correctly. They seemed to be pretty good results.
Matt