If you are talking about canned sodas, it might depend on where you live. Sodas are produced with local water and, travelling around the world, I’ve found a lot of variation on taste based on that. For example, Diet Coke produced in the south of France tastes awful. In Baltic cruises, you usually get cans from England, Netherlands or Germany and they all are similar but do not taste like DC from the U.S. or Canada. You might also see a difference if the can is getting old. The best before date is printed on the bottom.
If you are talking about fountain sodas, the water used plus the water/syrup ratio will give you a result that can be quite different from one machine to the next.