I knew the "At Last" performance would spark Beyonce comparisons since Beyonce's performance of the song is so famous. Well here's my two cents, Brandy did a great job and both ladies have beautiful, soulful voices. If I had to give my opinion as to who sings it best I think Beyonce has the edge. Beyonce has the unique ability to sound soulful, controlled, clear and classic all at the same time with such a high level of beauty in her voice. But, like I said, both can sing that song beautifully along with Christina (who maybe oversings it a little bit for my taste but still does great also).