Advantages of MBO
It reduces conflicts related to change since the objectives have already been set.
It reduces management work load thus giving managers more time to formulate new plans and strategies.
High performance is encouraged since everyone has to work towards the specified objective.
Disadvantages
Needs lots of paperwork thus bringing an extra cost.
Leads to rigidity since staff can only follow the specified goals, no divergent thoughts are allowed.
Environmental changes may weaken it
Advantages of MWA
Allows for innovative thinking since divergent ideas are allowed.
There is easy change in strategy in case of changes in environment.
It improves staff-management relations.
Less paperwork is required thus cutting on cost.
Disadvantages
Increases complexity of decision making since strategies are changed from time to time.
It is difficult to make long term decisions since strategies and plans change from time to time.
It may cause change related conflicts.