Our DD (AS/ADHD, aged 6) is on Concerta after a trial of ritalin (trial for effectiveness of the active ingredient for a week, concerta for long lasting effect of same active ingredient and only needs 1tab per day). She does take melatonin at night too.
It has helped in that she has pretty much stopped agressive behaviour (hitting, punching, kicking, biting) and while still sometimes using inappropriate actions (eg. licking), it is usually far more controlled. She is concentrating a LOT better in school, not causing ructions in creche (afterschool club), and is getting into a lot less trouble. Unfortunately, the older kids in creche had copped that they could do little things to rile her and end up her being the one seen to cause trouble before it started so, while she is less likely to react as badly now, she does still react at unfairnesses and perceived slights which are deliberate (I have seen it happen a few times, and so have minders on occasion - but often their back is turned so they don't see WHY DD is lashing out verbally - at least no longer physically too). And she is slightly less obssessive that she had been, and reacts better to changes in expected plans or routines than in the past.
We were talking last night about the tablets. (I am researching a lot recently as we only got the DX about 10 weeks ago, if even). She said that they help her a lot to feel better. She couldn't say why she feels better, but she does.
I am using the time until our next appointment with the consultant in October to look at other options (meds were very very heavily pressed on us, although she "couldn't recommend that route", but told us of all the reasons why we should use them and that there really weren't any other options). I hope to do some work on her diet and give her supplements over the summer, to see if that helps. (Her diet is reasonable, but she does eat some junk and I hadn't realised that the squash we drink has aspartamame).
But at the same time, while I am not mad about the idea of medicating for life, it has certainly made a difference at this stage and I will be very careful before I decide to take her off it.