When comparing Waffle.io vs Taiga, the Slant community recommends Taiga for most people. In the question“What is the best task management software for small teams?” Taiga is ranked 8th while Waffle.io is ranked 41st. The most important reason people chose Taiga is:
User stories can be organized in both Kanban and Scrum task management systems.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Free for public repos
Any public GitHub repositories can use the software for free.

Pro Links GitHub issues with a Kanban board
Existing GitHub issues can be used to create tasks and managed in a more convenient Kanban style.

Pro Real-time
Each update is visible as soon as it is made.
Pro Supports both Kanban and Scrum modes
User stories can be organized in both Kanban and Scrum task management systems.
Pro Free and open source
Taiga is licensed under GPL with source code available on GitHub.
Pro Simple to use
Pro Comprehensive Agile software development toolset
Taiga tries offering a complete Agile software development toolset. It includes complete solutions for issue tracking, videoconferencing, documentation (in the form of a wiki) and either a backlog or a Kanban board for managing user stories.
Pro Built-in issue tracking
Taiga has built-in issue tracking tools. The issues can be organized by user-defined type, severity, priority, creation date, assignee, creator, tags as well as filtered by subject. Taiga can also integrate with GitHub, GitLab and BitBucket.
Pro Built-in wiki
Each project has a wiki. It has Markdown support as well as a WYSIWYG editor.
Pro Built-in video conferencing tools
Integrates with either AppearIn or Talky to provide a video conferencing solution.
Pro Migration from RedMine
Pro Export/Import feature
You can extract all your data from one Taiga instance and move it to another one. You can read more here.
Cons
Con Managing large project may be difficult
Waffle works best with medium to small projects and very high-level general overviews and less with projects that require very granular management due to the fact that it becomes considerably more difficult to keep track of various cards and priorities as they are pushed off screen very quickly.
Con No Kanban metrics
Taiga is said to support Kanban but it does not generate any of the usual Kanban metrics (cycle time, lead time) or graph (Cumulated Flow Diagram).
Con Can be overwhelming at first
Taiga presents users with a lot of information and functionality right from the beginning with little guidance. Figuring how stuff works might take a bit.
Con Too much functionality for small projects
While it's possible to disable any unwanted features (modules), the amount of functionality that's present might be more than a small, short-term project needs.
