What are some alternatives?
When comparing edx-platform and Chamilo, you can also consider the following products
Moodle - Moodle - Open-source learning platform | Moodle.org
newrow - Create your online school and deliver interactive content.
Khan Academy - Khan Academy offers online tools to help students learn about a variety of important school subjects. Tools include videos, practice exercises, and materials for instructors. Read more about Khan Academy.
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.
Edmodo LMS - Edmodo is an easy way to get your students connected so they can safely collaborate, get and stay organized, and access assignments, grades, and school messages.
Teachable - Create and sell beautiful online courses with the platform used by the best online entrepreneurs to sell $100m+ to over 4 million students worldwide.