I have done my MBA from IIMC. And our batch had equal proportion of freshers and work-ex. It always helps to have work-ex. But it is not good enough reason for not appearing for MBA exams. If one is getting admission to very good MBA college, then s/he may leave work to join MBA. It has been observed in Indian B-schools , that if one has too much work-ex, s/he may find it difficult to find job. Of course ISB is an exception, but that exception or american B-school examples do not prove the rule.