API

Complexity

Complex and inconsistent

Consistent and dense

Test coverage for API

NO
Tested manually by users and contributors

YES
API is tested by unit tests

Learning curve

High
Mailnly due to inconsistency and workarounds and tricks used to overcome nature and limitations of PL/SQL

Low/medium
Need to learn RSpec and Ruby basics and how to use Array and Hash Objects

IDE support

No IDE support for API itself.
Running tests, reporting from IDE is not supported

Highly supported with JetBrains Rubymine (or IntelliJ)
Ruby, RSpec, Cucumber, Gherkin syntax highlighting and code completion
Test execution, exporting test results Support for GIT/SVN/Mercurial, PLSQL, SQL, Jira, Stash
and more (many of free plugins available)

Completeness

Medium

High

Integrates with CI (Jenkins)

not directly
Doable through external calls with Java and Maven
Integration suffers from API reporting limitations

YES
CI-JUnit Reporter plugins available

Documentation

Incomplete online documentation

Everything described by examples
Concept of self documenting tests