Disclosure: I received this product for review in exchange for my honest opinion.
Ok so typically I buy water whenever I want it if I can. I like it cold and I can not stand the stale taste that water that has been sitting in a water bottle all day has. So when given this bottle to review I was worried that it would have the same issue, I however was pleasantly surprised. The ChillWarmer insulated hydration bottle really didn't give the same metallic or stale taste to the water after prolonged periods in it. I also wanted to evaluate the ability to maintain temperature throughout the day. The way I tested this was through a time course study at work. Yes, I am going to get all nerdy on you, and yes I have a control as well..... No judging science nerds. These were both tested qualitatively however since I didn't want to use a lab thermometer on something I was going to put into my mouth.
For the first experiment I placed Ice water in the ChillWarmer, at about a 40/60 ration ice to water. From the addition the ice began to melt as expected until the water got cold enough to slow the melting. After which I left the water/ice mixture in the ChillWarmer and checked it after 5 hours. At 5 hours there was still ice when I checked again at 8 there was not but the water was still cool. That being said I had a new question how long will it just maintain without any state change. So I put in cold water this morning from the fridge so about 4 C ish... then I waited, 6 hours this time and it seems to have maintained the cool inside as it feels to be about the same as when it went in. I also had the rest of the bottle on the counter and it has definitely gotten up to room temp (see my control). Overall I would say that this product will maintain the cool very well for hours.
As for the taste the other item I wanted to test qualitatively, I can personally attest that it did not have any weird metallic taste from the bottle or did it taste stale after 6 hours. Overall that is a win for me.
My only potential down sides from it are the amount of liquid it can hold. At 17 oz it's a bit small relative to the size and if you were going to pour a 20 oz bottle of water which most are about it wouldn't all fit. Also the locking mechanism on the top lid feels rather flimsy. I suspect it will get some damage at some time being tossed into my monster gym bag. But for someone who treats their things well this is definitely worth the cost.