My children enjoy using this thermos -- they each have one. I appreciate its wide neck, in-built foldable stainless steel spoon, and appealing appearance. So far, my children have found the heat-keeping capacity good, from morning packing of lunch till lunchtime. After school, and even quite late in the evening, I find the contents still warm, though not hot.
The price of this jar, at the Eco Store, is also very competitive.
The only possible drawback would be the need to hold down the button in the screw-top lid in order to release the pressure and make it possible to unscrew the lid. It can take a while (10 seconds) of holding down the button before the lid can be unscrewed. My children take this in their stride but it may take a bit of getting used to, especially for a young child (say, aged 4),