Fat Pepsi in a 2L bottle has sugar and artificial sweeteners. Fat Pepsi from a dispenser, ie pubs and fast food joints, doesn't have artificial sweeteners. Not looked at fat Pepsi cans.
Fat Coke 2L has seemingly gone, replaced by a shrinkflated 1.75L. Had a can of fat Coke with a meal in the week. That was unchanged -Full sugar ahead.
Tried fat Barr cola, another sugar and artificial sweeteners car crash. Didn't like the Fever Tree fat cola either. Had hoped the stevia sweetened Green Cola was going to be as good as their sour cherry, sadly it wasn't.
What I'm taking from this half arsed anecdotal survey - Fat Coke in cans is the way to go for occasional drinkers and as a superior mixer.