Sugar please. I can't stand the taste of aspartame. They've started using Dextrin to replace sugars in confectionary (Mars Galaxy minstrels) and they taste awful.
I liked Pepsi more than Coke but now that in the UK is using Aspartame in Pepsi it ruins the taste tenfold.
Sounds like aspartame is a boon for your health if its addition means you eat fewer Mars bars and drink less sweetened bubbly water. Hooray for aspartame!