Sugar CRM open source and Proprietary difference

Hi

I am working as an IT head and recently implemented Sugar CRM ( commercial open source licensed versions) , I want to present to the management the advantages/benefits of sugar crm when compared to the other Proprietary CRMs, Access to Source Code is one which I am aware , can anyone help with more information so that will make a note of all these points , I wanted to present how are we going to be benefited due to the open source when compared to the Proprietary

Thanks in advance