Some people's palates pick out the "artificial" sweet taste of artificial sugars better than others. If you don't like the artificial sweetener taste in Diet Coke or other ubiquitous "diet" drinks, you aren't going to like it in your beer.
Do you happen to keg? You could cold crash in the keg and easily sweeten this with the same mint syrup used in most mint julep recipes. If you bottle, this probably isn't an option, as the backsweetening procedure for fermentables in a bottle is a real PITA, in my opinion.