FWIW, I found practically no information regarding aspartame on the University of Sydney site, but I did come across an article that basically said stevia and aspartame both work, but stevia was was significantly better at lowering blood glucose levels.
Sidenote: As someone who loves beer dearly, but also tries to limit his intake of foods with a high glycemic index, I was pleased to read an article [2] linked by the University of Sydney [3] about how beer has too low of a glycemic index to measure (still has plenty of calories, though).