In vocal music, conjunct motion is often considered better because it involves pitch movements that are close together, making the melodies smoother and easier to sing. This type of motion typically allows for a more lyrical and connected sound, which is desirable in vocal compositions.
Disjunct motion, on the other hand, involves larger intervals and can create a more dramatic effect but may also be more challenging for singers.
So, the best choice for vocal music is conjunct motion.