We use Antlermax 20. We have used it for about 9 years. We have tried other products in the past but have had the best results with Purina. The product is consistent and we don't have to worry about feed - there are enough other things to spend our time on. Also, if you are having an issue, there is a Purina rep available to help you out or come out and do a herd check. We had the opportunity to visit their research facility in St. Louis and. I can tell you we were impressed. They have been in business over 100 years and are continually improving their products. They have some new products that are less expensive too, I believe their Advantage line has the solid basics but costs less.