When comparing Spine vs Anima2D, the Slant community recommends Spine for most people. In the question“What are the best 2D skeletal animation tools?” Spine is ranked 1st while Anima2D is ranked 5th. The most important reason people chose Spine is:
Ranked in these QuestionsQuestion Ranking
Pro Integration libraries support most engines
Pro Simplified UI allows for an easy learning curve
No-nonsense workflow allows you to create your artwork in programs much better suited for the task like Illustrator and Inkscape for example, while Spine itself focuses only on the important task of skeletal animation.
Pro Allows for easy use of artwork from third party programs
Spine's developers provide scripts which makes exporting artwork from third party programs much easier to do.
Pro Community-driven feature roadmap
Esoteric Software maintains public Waffle issue trackers to help plan and prioritize feature additions.
Pro Price high for this product
Pro Purchased by unity
Everything you could want from a skeletal animation system, free and because purchased by unity promises to be native in future.
Pro Spring bones
Much like spring joints native to unity, you can set bones to have dynamic spring animations based on their parents.
Con Spine Professional is expensive
Spine Essential includes nearly all features, except IK, weights, and meshes. Spine Professional is expensive, though it does give all future updates for life (Spine is updated very often).
Con No integration for lesser known engines
Spine does not directly support some game engines, such as Construct 2 or Clickteam Fusion.
Con Uses the Unity hierarchy
It's impossible to rename your asset after making your animation, otherwise you lose dependencies.