I love it. It kept the water hot for hours. I used it on a day trip we had planned, and I wasn't going to have access to warm water. The water was still warm hours later when we got home. I highly recommend it if you are out and about with your little one.
We used it during a trip out of state and it worked wonders! It easily and quickly warmed milk out of the fridge without any issues. The hot water kept for several hours, and I was able to boil water the night before and it kept hot enough for us to use until the following day.