? Pre nu 52 Atom Smasher was Al Rothstein not Pratt ( Al Pratt was his god father the original Atom).
Atlas has a distinct strength advantage as AS was only a 70 to 80 tonner at base strength ( increased a little when he grew with giant power). He could only mix it up with the likes of Black Adam etc because he could alter his mass and density as well as size. Making his punches have more striking force than his strength alone would give because the mass at its acceleration increased. Still lean toward Atlas