To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
We bought these for our kids (aged 6, 8 and 10) for Christmas. I love that they can't do anything else but listen to music (no you-tubing etc). I download all their favourite songs and also meditation/relaxation music. They love having their own playlists and I love the quiet times. The device is fairly easy to set up. I recommend using a Youtube converter to easily convert your favourite music into an MP3 file.