Review (4/5): Quieter than regular clippers, but best for thinner hair....
My children don't like haircuts, but my 6 year old has an especially hard time with it. While these seem mostly targeted to babies, I decided to give them a try for my older children. These clippers helped the process and all of my children preferred them. That said, these do work better on thinner hair. My two older children have thick hair and these clippers struggled with it. I ended up using another pair of clippers to thin their hair out a bit before swapping back to these. I didn't mention trying new clippers or explain the swapping back and forth, but they still requested I go back to these. These clippers do still make noise when in use, but it is more muted than regular clippers.
Overall, I'd say these are great to use on thinner/finer hair, but for thicker hair, just be prepared to thin it out first. Other than that, I've been super pleased with them.