Hi Steve, We got along pretty well with the Standard rotor. In standing milo it worked great as long as we were up above the leaves. One morning my Dad was just getting started and let the header dip down a little too far and the rotor just stopped. I wasn't there, but they spent the rest of the morning digging it out. That can happen with a Specialty rotor also, but we've rarely done it. It is a lot harder to do it with a Specialty, that's for sure. I couldn't find anyone who has ever plugged a St. John rotor. If they have, please get on here and post. It is my impression that the St. John rotor can handle the toughest crops, meaning green milo, green wheat straw, weedy milo, green stem bean, rice, etc. It is also supposed to have less rotor loss than the Standard, which we felt lost less than the Specialty. It seems like the St. John rotor has all the advantages of the Specialty and the Standard, except that a chopper is required for no-til. It does not grind up the straw like a rub bar rotor. Maybe we can get some rain so that I can find out next summerIJ