Open source is an attractive option allowing the user the ability to customize as they see fit.  However, for established businesses, the lack of documentation and support often makes it too risky to transfer over their existing systems.  For this reason, I am very happy to see the growing number of hybrid models with an open source version and a paid version, both containing full documentation and professional services.  It takes away the danger of testing the application while giving a clean path to scale and strengthen the development with additional support, once the value of the product has been established.