When comparing Spine vs GAF:Flash to Unity, the Slant community recommends Spine for most people. In the question“What are the best 2D animation tools for Unity?” Spine is ranked 3rd while GAF:Flash to Unity is ranked 8th. The most important reason people chose Spine is:
Ranked in these QuestionsQuestion Ranking
Pro Integration libraries support most engines
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 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 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 Supports different frameworks
Full playback API supported in Unity3d, Cocos2d-x, Cocos2d, Starling.
Pro Alows using Flash animations in Unity
You can convert Flash animations directly in Unity with the help of plug-in. The converted .gaf file consists of a texturte atlas and a binary config.
Pro No need to use large Sprite Sheets
With GAF converter you get a highly optimized texture atlas and a config file. You don't need to take trouble over cumbersome sprite sheets. You can easily modify an already working in Unity animation and play around with the animations parts whenever you need.
Pro Can convert 99% of what can be done in Flash
GAF supports such Flash features as:
No limitations on timeline;
Conversion of shape tweens;
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 Sound support available only in Premium version
GAF Converter supports sound but only in the Premium version.
Con Doesn't support sounds
GAF does not support importing audio along with Flash animations.