I don't really care for aspartame due to taste. Sucralose AKA Splenda has been determined to be safe and has had over 25 years scrunity. Pepsi used to make a drink called Pepsi One and it was sweetened by Sucralose. Ingles in store brand of diet Cola also uses it and it taste pretty good. Personally I've never had any trouble loosing weight using Splenda. But I'll pack pounds on fast if I go back to regular sugar drinks. Sucralose is made from sugar BTW.
Aspartame really took the pizzazz out of Fresca that cyclamates (which are still legal in Canada) gave it. Aspartame makes Fresca pedestrian. Even saccharin would produce a superior Fresca, IMHO.