So I tested this to hold water for baby formula on a road trip. Water went in at 95 degrees Celsius and with a full bottle took around 7 hours to get down to 70 degrees....the minimum temp to make a bottle up.Tested again by waiting for water to get to 80 degrees (3-4 hours) then pouring a bottle (210ml) and I still had an hour and a half to make another before the water got too cold.Very sturdy even after my toddler has thrown it around, leak proof, gorgeous colour and keeps my much needed coffee hot all day if needed, as a mamma of toddlers you don't often get time to finish a hot drink in one go so this definitely does the trick. Not tried for cold drinks yet.So far so good. Look good and keeps drinks cold for hours! Haven't tested it with hot drinks yet. Only thing that annoys me is that the flower bottle cover has a visable line so would look better if the logo were on the other side, but that's purely cosmetic.I like this bottle because it keeps cold water cool and doesn't spoil the taste of the water. The mouth of the bottle is big enough to fit ice cubes in so I will definitely be using it when I want to drink ice cold water in the hot summers. The bottle is strong, heavy duty and will probably last for a long time. I don't intend to use it for hot drinks but I can imagine it would keep hot drinks hot for while.