Research results notwithstanding, my anecdata suggest that sugar soda tastes better, and I am not quite sure why. I think it might have better flavor overtones or better mouth feel or something. Less gluey somehow even though there shouldn't be any difference. Maybe the sugar recipes are better in ways unrelated to the sweetener (and bottled soda is also usually better than canned, but fountain sugar soda still seems better than fountain corn syrup soda) or maybe the processing is subtly different.