We have used Vyvanse (new in the last four years and great for us) for three years for a son with ADHD whose biggest hyperactivity is pencil tapping. Before you switch any medication, may I suggest documenting the "inefficiency" of his Concerta. My son's psychiatrist cautions us not to expect perfection with attention as we would never expect this from the other four children. Sometimes life is exciting and it is hard to pay attention under the best circumstances.
We also give my son the weekends and vacations off from his medication since he really likes to take it for school but has recognized the medication has a restrictive impact on his natural personality and he likes to feel "himself" whenever he can afford the luxury. The week prior to the December break, he had homework every single day (even on the last day of his fifth grade break-unusual since the teachers usually ease up)but I always try to recognize the difference between many distractions and medication problems. Not everyone recommends the halts in meds but it works well for us.
I no longer worry about other people's opinions about the stimulent he requires since even my son notices the large improvement the medication seems to make and our quality of life has greatly improved at home and at school. My thoughts are with you as ADHD calls for difficult decisions and much agony in children and parent's lives. J.