For what it's worth, I've had very good success with neurofeedback for my anxiety. (I don't have ADD.)
But I think you need to find a VERY qualified therapist... do research and get recommendations.
There's a new book out (came out this month) called "ADD: The 20-Hour Solution" by Mark Steinberg and Siegfried Othmer that explains how neurofeedback works.
One of the challenges that neurofeedback is facing is the lack of research that would validate it in the eyes of MD's. But I think that will change soon. Also, another thing to consider is that it's not an overnight solution. The above book calls it the "20 hour" solution, but what they mean by that is 40 thirty-minute therapy sessions. So if you're going once a week, that's close to a year of therapy. So when people tell you it's a waste of time and money, it could be because they gave up before they started seeing results. I think it can take 10-20 sessions before noticeable benefits kick in.
I'm not a professional, I'm just a satisfied neurofeedback patient.