In my experience the one in Spain is less sweet than the one in the USA. Same in France.
I recently travelled to France and the fridge was so cold it had frozen half of the coke. Then I tasted it and it felt like the USA version. But then I realized it was because most of the water was still frozen while the rest of the Coke was already getting unfrozen and felt more concentrated/sweet.
For a day I thought the Coke in France was also sweeter.
Same sort of experience. It tastes the same in the UK as it does in Spain.
In my experience the one in Spain is less sweet than the one in the USA. Same in France.
I recently travelled to France and the fridge was so cold it had frozen half of the coke. Then I tasted it and it felt like the USA version. But then I realized it was because most of the water was still frozen while the rest of the Coke was already getting unfrozen and felt more concentrated/sweet. For a day I thought the Coke in France was also sweeter.