Both my 8 and 9 year old son and daughter have this neck brace and they are perfect. They are easy to take on and off and they offer a ton of neck support. They took 1 day riding to get used to. Now, they wont ride without them.
Bought this for my 8 year old son. He loves it and as expected he got fearless once he put it on. He had a pretty gnarly crash shortly after putting it on. Given it's only been through one crash but it held up fairly well.