Rotation Defense, or Man Back, is probably the most common defense played in Women's Volleyball.   The goal is to cover a mix of tips and swings.

Strengths:  Covers tips directly behind the block, and hits deep line.  Setter transitions quickly from offense to defense.
Weaknesses:  Requires a lot a movement (transition defense is a severe problem),  middle back is wide open against many outside attacks, seams are created between wing defenders because of the all the movement required.

Rotation Transition Weakness
   The middle back player is required to move from coverage of the outside hitter to their defensive position.  Reversing the attack (OH to OH) will make the MB players move a great deal in order to go from hitter coverage to defense.