Great for 3-year-old's straight hair
Perfect for toddlers/young kids.  Agree with other reviewers that the bristles are not too soft like baby hair brushes, but not as stiff as regular (teen/adult) hair brushes.  I use it on 3-year-olds hair, and they brush their own hair, too.  Theirs is straight hair, I would say medium weight hair (not fine, not thick).  I have not tried it on curly hair.
Rating: 5 stars