I bought this to carry extra food on long days of class and/or work or other adventures in case there is no refrigerator available; it has definitely been a worthwhile investment. Contents stay cool for multiple hours depending on how packed it is; I pack a mixture of rice, lentils, potatoes and small veggies (basically a utilitarian stir-fry) and it is still cool after about 3 hours. Putting the loaded container in the fridge the night before also helps ensure things stay cool, about an extra hour. It can be a pain getting food in this thing; the mouth is not very wide, so paying close attention while putting food in it is a must.
Overall though I am completely happy with the purchase. I haven't tested how well hot food stays hot in this thing, but I plan to this winter and I have no doubt it will do well; if it is anything like the flask I use for drinks (in which after 2 hours on a winter hike a cup of hot tea is still too hot to drink), I am supremely confident it will perform well.