I've had this Ninja Thirsti travel bottle for about a month now and am using it almost daily.  I've had hot liquids in it, like hot chocolate, but have mostly used it for water or diet soda that I drink.   I usually go for lunch to places with soda fountains, and I get my refill of soda put in the Thirsti, and it keeps it cold for hours.  And I've had soda in it overnight and it always keeps in the carbonation to keep it ready to drink.   I also use it for water for my workouts and have left it out in the sun for hours and the water still stays cold.   I like it's skinny enough to fit in the side pocket of my backpack, so I've taken it on trips as well.   And I really like there are two flat side to the bottle which seem to make gripping it easier.  So overall a great insulated bottle that will keep your drinks hot or cold and your soda fizzy!    Would definitely recommend.  Ninja comes through again!