What are some alternatives?
CodeClimate - Code Climate provides automated code review for your apps, letting you fix quality and security issues before they hit production. We check every commit, branch and pull request for changes in quality and potential vulnerabilities.
GitHub Reviews - A place for reviews of popular open source projects
Codacy - Automatically reviews code style, security, duplication, complexity, and coverage on every change while tracking code quality throughout your sprints.
Bookmarking for GitHub - Save and organize your favorite GitHub repositories
SonarQube - SonarQube is code review and management software. The software is developed by SonarSource, which was founded in 2008 by Freddy Mallet, Simon Brandhof and Olivier Gaudin. Read more about SonarQube.
Swyya - Find trending open source projects to contribute to