What is the best legal structure for incorporating Project AiAi?

AiAi is a collaborative code-charity project working to create world's first free, open-source Radiology Computer Aided Detection (CAD) algorithm for Lung Cancer. This CAD will be licensed for free to developing countries like India, Belarus, Vietnam, and aid organizations like Doctors without Borders.

Once published and operational, it will be easy to modify AiAi source code and create more CADs for additional diagnoses and modalities like MRI, CI, PET, Ultrasound, and XRay. Therefore, we view AiAi as a seed-project that can grow bigger and provide free alternative to expensive commercial CAD software from companies like GE, Philips, and Siemens.

With this goal in mind, what is the appropriate legal structure to incorporate Project AiAi? Would it be a 501(c)(3) charitable organization, or LLC?

Please edit the wiki to share your thoughts.