Open-source software is free of licensing fees. Furthermore, it is easy to adapt and enhance by new features. Nevertheless, using open-source frameworks is not for free. Like in closed-source software, not everybody is an expert for any framework. The total cost of ownership also includes training, adoption, enhancement and maintainance of a framework. It might take significantly longer for somebody new to the project to extend a certain feature than for the person who introduced it at the first place. Furthermore, software has to be maintained. Even if this can be done literally by everybody for open-source software, a professional maintaiance agreement with fixed response times is often manditory in an industrial setting. This ensures your productivity. EclipseSource employs several EMFStore committers and offers professional support and training.