I have been on something of a campaign against makgeolli with aspartame. I mean, if it's a traditional Korean drink that's part of the "well-being" craze in Korea these days, should they really be putting toxic chemicals into it? Doesn't make it any worse than Diet Coke, but I'm not sure that's the kind of comparison they want people to be making. My post from last month, "New" is the "New Old" in Korea Today, goes into a bit more detail on this.
Anyway, I have personally verified that aspartame is in the ingredient list of every one of the following makgeolli brands. (The guy at Lotte Mart watching me checking bottles and photographing them didn't look too pleased.)