If you are still in searching for good technology, then SAP BO is very good Tool. It is not mandatory to know SAP BW. But Some cases when we are trying to use the SAP BW data into BO Tools, we have to integrate BO to SAP. Then there is a simple process of transporting the SAP Data using this integrator. So go ahead with SAP BO. All the Best.
Now in Next Version of SAP BO 4.x, it is not mandatory to know about that integrator also. But as per current version you have to know about it.