When comparing Thinkster 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 Thinkster is ranked 16th. 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 Real-world projects
The tutorials walk you through building different apps such as a Slack clone and simplified Google+ clone.
Pro Available online, as a PDF and screencast
Depending on your needs or wishes you can get the ebook, screencasts, sample code on thinkster.io.

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 Monthly subscription to access videos
With a free account, you are able to view all the text in a tutorial. However to view the videos, you have to sign up for a monthly subscription ($19/month).

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.
