When comparing Apiary vs Yesod, the Slant community recommends Yesod for most people. In the question“What are the best Haskell web frameworks for building RESTful web services?” Yesod is ranked 1st while Apiary is ranked 11th. The most important reason people chose Yesod is:
While not required, Yesod offers templating through a Shakespearean family of languages to produce page code.
Specs
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Pros

Pro Automatically generates API documentation
Apiary generates comprehensive HTML documentation based on your API routes.


Pro Type-level routes
Apiary provides type modeling, down to URL parameters, ensuring type safety.
Pro Offers templating for type-safe, well-formed content
While not required, Yesod offers templating through a Shakespearean family of languages to produce page code.
Pro Uses type-safe URLs
Ensures that data provided by the URL is type-safe. This means that data in the URL has a definitive type.
Pro Can be used without knowing much Haskell
While Yesod is written in Haskell, developers can achieve basic functionality without much investment in the language.
Cons

Con Mediocre documentation
Users must rely primarily on the example project and auto-generated API documentation (Haddocks). The author of Apiary is not a native English speaker and openly acknowledges this issue.
Con Is hard to customize
Learning how Yesod works internally is hard. It is a large framework with complicated components. Finding the appropriate code and understanding how it contributes to the framework is difficult, meaning developers will struggle.
Con Too much template haskell
You actually want to code in haskell and not some DSL with "magic" hidden under the bonnet.
