When comparing The Little Book on CoffeeScript vs exercism.org, the Slant community recommends exercism.org for most people. In the question“What are the best resources to learn CoffeeScript?” exercism.org is ranked 1st while The Little Book on CoffeeScript is ranked 5th. 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 Intent of CoffeeScript explained by creator
The last chapter is written by Jeremy Ashkenas, the creator of CoffeeScript where he explains the theory and intent behind CoffeeScript
Pro Concise introduction
"The Little Book on CoffeeScript" does not go into depth. Instead, it covers the syntax and all of the available features of CoffeeScript, giving the reader enough knowledge to learn more advanced CoffeeScript with ease.
Pro Free
Available online for free.

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 Not much information past the very basics
The books is just under 50 pages so it can't cover much.

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.
