i would check out the 916AT -- i did have a 607A and sold it. but to the balls defense i dont believe i had the correct lay out, because it just didn't react like i wanted it too. i was going to get another and drill it differently, but then i herd about the 916AT that was going to come out, so i waited for it. im really glad i did. i am definitely getting the reaction i was looking for with this ball. the 916AT just flat out works. im not saying the 607A will be a bad choice, but i absolutely love the 916AT.