Bests & Worsts Reviews from Amazon

I just received two of these in the mail four days ago. Yesterday, I washed them thoroughly, filled them with hot water and sealed them for 25 minutes. Then I dumped the water and filled them with piping-hot soup. They sat in my car in the full sun from 9:00 a.m. until 2:30 p.m...even the exteriors of the containers were warm from sitting in the sun. When I opened them at 2:30, the soup was very lukewarm. Super disappointed, and will be returning them. I give it one star for the amazing spoon, though! Does anyone else find it weird that the reviews are at two ends of the spectrum? Either the Thermos works like a charm, or it simply doesn't keep things hot, as in my experience. Very curious.