edX vs exercism.org
When comparing edX vs exercism.org, the Slant community recommends exercism.org for most people. In the question“What are the best websites to learn to code?” exercism.org is ranked 2nd while edX is ranked 4th. The most important reason people chose exercism.org is:
Rather than merely test for code correctness, Exercism uses peer review to improve general programming techniques. Users are encouraged to comment on others' solutions, and refine their own based on feedback.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Free
Both edX and the classes are free.
Pro Offers courses from well known schools
edX offers courses from a wide range of well known colleges and universities including Harvard, MIT, UC Berkeley, Cornell and more.
Pro Large selection of science courses
edX offers a wide variety of science-related courses. This makes it a great resource for learning not only specific programming languages, but also other topics relating to computer science.
Pro A lot of topics (subjects)
Topics include biology, business, chemistry, computer science, economics, finance, electronics, engineering, food and nutrition, history, humanities, law, literature, math, medicine, music, philosophy, physics, science, statistics and more.
Pro Offer certificates for some courses

Pro Human review and feedback
Rather than merely test for code correctness, Exercism uses peer review to improve general programming techniques. Users are encouraged to comment on others' solutions, and refine their own based on feedback.

Pro Practice with production tools
Unlike many code practice websites, Exercism requires the user to develop and test entirely offline, submitting only the finished code. This promotes familiarity with essential tools and workflow, not just the bare language.
Cons
Con Lack of engagement in the forums
edX does not have the same forum participation from both students and instructors that other websites do, and the form of engagement often does not encourage discussion.
Con Courses aren't always available
While edX does offer some self-paced courses, you may end up waiting for the course of your choice to be run.
Con The forums are difficult to navigate
The forums are difficult to sort by date and topic, and are unintuitive to navigate.

Con Custom commandline client
Exercism requires using a CLI utility to fetch and submit exercises. This is inconvenient compared to web-only alternatives, and poses an additional barrier to entry for some users.
