I had the chance to talk to the parents of the kids (and a couple of the kids) of my son's D&D4 group.
The big news is that they all had a good time. The biggest surprise to me though was the the ones that enjoyed it the most were the youngest one in the group. My youngest (9) loves his Bard. The two younger kids (almost 9 and 8) also really like their characters and they like the system.
All three were told by their parents that if they didn't enjoy it they did not have to stay. But so far all three are staying.
The older kids had fun too. They had more opinions on what worked and what didn't. My oldest son still enjoys 3.x more he thinks, one of the twins loves his character so as long as he is playing that he is happy. The other twin prefers C&C, but that is fine.
The next game is July 16. We have mysteries to solve, some kobolds to take care of, and there is that rumor of a dragon's graveyard.