My 5 year old son has tried focalin. At first I could not tell a difference, then it seem to start working after about 2 months. Then one day it seem to work to well and he was really spaced out. When the medicine stopped working in the afternoon he was wired and was very aggressive. I stopped the focalin and took him back to the Dr. The Dr. didnt seem concerned about it and changed him to ritalin. The Dr. seemed to think maybe it was because he was still so young. Hope this helps.
My 12-year-old son takes 15 mg Focalin XR on school days; sometimes we add a 5 mg short-acting Focalin booster at 4 pm for homework. He felt flat and inhibited on Concerta, Strattera gave him full-blown migraines (in spite of being on preventive meds for migraines) and Adderall caused his facial tics to be much worse. I think Focalin works really well -- smooth take off and landing, a bit of appetite suppression at lunchtime but not major (Concerta was worse) and focus without flatness. As you may know, Focalin is a refined version of Ritalin that is supposed to cause fewer side effects. It's tops in our book, but of course, every kid is different and ADHD meds are frequently trial and error. Good luck with your decision.