Which is better, being set is more powerful but is it more effective? How do you box if you have to keep getting into a position stopping then punching, then getting into position again, seems mad. Hows it done this way? It seems far more fluid and effective to always be moving and to be able to punch while moving, is it?
They are both stepping and punching. Obviously Frazier's punches is going to have more power as he is step in with his shots as Ali is stepping away.
There is no 'better'... there is only more appropriate and effective at a given time. A one trick pony rarely gets anywhere...
Of course depending on your opponents style, a Mobile Boxer like Ali can use his opponents forward attacking momentum against them, but if you bob and weave and come in behind a Jab..maybe not...no right or wrong way, just a different way, one's physical build, may dictate your style, then its up to you to hone that style to its optimum effectiveness. Also of course the Mental battle then has to be won. thats why world champs come in all shapes, sizes and styles.