Go for functional module...depends on your area of specialisation...SAP-Basis is too technical and gets stagnant from a career growth point of view. Functional Consultants are the long term preferred choice for Project Managers but not SAP-Basis guys.
Hey mate...am writing my dissertation 'Benefits of Lean Management and ERP Implementation'. It will be very helpful if I can get some questionnaires regarding Lean Management and ERP implementation