We use them for our 3 and 5 year olds and have been VERY happy with them! Dr. Brown and her staff are great with kids and have sweet perks like flat screen on the ceiling above the dentist chair where the child can pick a dvd from their library to watch!
We had an emergency situation about a year ago when my then 4 year old fell and knocked out his 2 front teeth. They not only made special accommodations to help my son through the extractions, but also were there for me as I was a complete weepy mess!