My 3 year old loves hers. I haven't had any of the battery issues I see others complain about. I got six months out of it easily using it twice a day. I had to replace it because it was worn...not broken. Also my three year old has no problem turning the brush on.
My 8 year old and 10 year old love this toothbrush because it lights up. I can finally get them to brush for the recommended 2 minutes. Unfortunately, the battery ran out withing 2 weeks of using the toothbrush. I don't know if the battery died becasue it was on the shelf too long at the store... or weather my son kept "turning it on" to see the flashing lights. I hate the idea of having to throw away a perfectly good toothbrush so soon. I wish I could replace the battery.
This product is a great idea, but very hard for my 7 year-old to turn on. He doesn't have the strength in his fingers. So... now I have to go in the bathroom with him to get started.