Cleans and Hi-Pulls are excellent for the whole chain of back muscles, from the traps to the small of the back. That would include those muscles running all the way down to the calfs/ankles. Are very effective for the delts, both rear and side. All around mass builder.
Some may have trouble with the wrist flexibility, which in return can cause pain. If you are raising the elbows up high enough (which most BB'ers are prone not to do...check out some video's of Olympic lifters for hints) and allowing the hand/fingers to catch/set the bar on the base of the front delts, a lot of the wrist problems should be reduced. Too close or wide a grip can also cause some problems. The more reps you get in the better the over all flexibility of the wrist/elbows. Practice with the bar only for a while to learn better form. A added suggestions is that the foot placement and even the toe griping has a bearing on a good clean. That's where it all starts from anyway.
When cleaning from the floor I will do the deep squat clean version. Almost like a high raising DL and than getting under it as fast as you can. Prefer rack over floor cleans/Hi-Pulls. Usually hit either one twice a week. Try getting away from lower reps and get to 10 to 12 reps range. See how that may affect muscle building and stamina.
Might also try two hand DB cleans from the floor for a whole new experience. Also the one arm DB Hi-Pull, from a hang position, are excellent for raw power. If anyone is into athletics than consider these two DB versions for position and functional (over used term I know..sorry) strength. Good Luck.