I don't have ADD but used to take 5-50mg/day for a few years. It was great for slamming out 8-hour work dumps. Until it wasn't...
So long as I had my basic work-plan on paper before I took a single pill, things usually went very well. Never had more fun working in my life!
Music blasting, tasks doing themselves, making 50k/mo, in my 20's and full of pharma-grade speed.
Loads of side-effects, especially for non-ADD folk taking higher doses. Very ugly in the end.