It is in sweetness of melody and its charm; in exquisite fitness of its music to its thought and its emotion; in lawful change of harmony making enchanting variety to the ear; in the obedience of the melodies to the laws of the different kinds of poetry; and in the lovely conduct of the harmonies, through all their changes, to that finished close which throws back its own beauty on all that has preceded it.

This part of the loveliness of form in poetry, along with composition and style--for without these and without noble matter of thought poetry is nothing but pleasant noise--secures also the continuous delight of men and the approving judgment of the future; and in this also Tennyson, who gave to it the steady work of a lifetime, stands above his brother-poet.
Browning was far too careless of his melody.

He frequently sacrificed it, and needlessly, to his thought.

He may have imagined that he strengthened the thing he thought by breaking the melody.

He did not, he injured it.