I bought one of these for my 5-year-old daughter (and the planets for my 6-year-old son). We've had them for about a month and the quality appears very durable. I hand wash the top and bottom as suggested.

I pour boiling water into the container, let it sit about 5 minutes while I heat up lunch. Then I pour out the water, put in the food, and close right away. The food stays quite warm until lunchtime (about 12:00). It holds exactly one can of ravioli. The containers are spillproof yet easy to open.

My daughter loves the ballerina on the container. This is a key issue for ensuring she'll eat all of her lunch.