The ease of use, the fact that it's been designed for multiple applications, and the ability to store blood in the system. It takes some time to learn how to make effective connections with the machine, but once you do it's very easy to use. I would recommend this product as it has many uses, including treating autoimmune diseases and other conditions such as lupus. It makes life easier by making it possible to perform more therapies without having to go through the process of connecting multiple bags of saline to the machine.