I bought one of these from Costco for my wife , and I CANNOT BELIEVE how long it stays cold. I filled it up with tap water last night, added about 6 ice cubes (which is not a lot for how big this thing is) and have been drinking from it for 24 hours without refrigerating it or adding more ice. It is still ice cold and feels like I just pulled it out of the refrigerator! I cannot believe it as most thermos products have not lived up to my expectations on temperature retention. I might be buying a second one for myself! I haven't noticed any leaks, and even though the body isn't hand washable I had no trouble cleaning it before using.
Rating: [5 of 5 Stars!]