Took all 3 at different times. Concerta is once a day, works good for me, and other people who have tried it. Works for 10-12 hours or so. Ritalin is good for short periods, tkae it a few times a day. Havent had adderall in a while, but XR is similar to concerta and I hear it is very good, and almost a little better than concerta for some people. It really depends on the person I think, and if they want a somewhat lower once aday, or stronger several times a day.