Some people think that the acid in soda eats away at the lining in cans which gives it a slightly different taste. Plastic? Dunno. I worked at a movie theater for a short stint. One of the tasks was to refill the soda fountains. That basically involved replacing a box with a plastic bag containing the soda syrup on a shelf and sticking a nozzle into it. Logically a soda from a fountain should taste the same as one from a bottle. Two liter bottles going flat non-withstanding.