I will jump in here...
My daughter has been flying F or Business international since she was two. I have had FA thank my husband and me for having such a polite child. Compared to the drunk adults, there is no question that she is better behaved.
I think that without question, when traveling with a minor, be it in First or Coach, is all a matter of expectations. We expect good behavior, and only exceptional behavior is rewarded (e.g. no flare ups during long delays or missed connections). That said, I have no patience for people who complain about kids but say nothing about the drunk idiot who is watching soft-porn on his laptop in full view my fourteen-year-old daughter.
Honestly, can't we behave in F (or on a plane for that matter) as we would in a nice restaurant? *sigh*