When comparing SmoothMoves vs 2D Toolkit, the Slant community recommends 2D Toolkit for most people. In the question“What are the best 2D animation tools for Unity?” 2D Toolkit is ranked 3rd while SmoothMoves is ranked 8th. The most important reason people chose 2D Toolkit is:
The documentation for the toolkit is well written and there are video tutorials as well as an active community.
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Pros

Pro PlayMaker integration
Developers echo17 provide Playmaker action scripts for SmoothMoves.

Pro Texture swapping and tinting at runtime
Animations can be re-skinned in several ways, entirely on the fly.
Pro Good documentation
The documentation for the toolkit is well written and there are video tutorials as well as an active community.
Pro Includes source code
No need to pay more to get access to the source code.
Pro Pixel-perfect camera
Pixel games in the style of 8 or 16 bit systems need to have each pixel uniform on the screen which 2D Toolkit supports with a camera component.
Pro Add colliders in the atlas editor
Choose from either a box, sphere, or mesh collider that will output as either a 3D or 2D collider in Unity.
Pro Create different resolutions of atlas
2D Toolkit allows for different sizes of atlas from 1x, 2x, or 4x which can be changed depending on platform resolution.

Pro Built to work inside Unity
2D Toolkit is an editor extension so users don’t have to leave the Unity engine for tile mapping.

Pro Create Atlases within the tool
Create sprite sheets for tiles to save draw calls and to keep tilesets organized.

Pro Supports the Tiled TMX Format
Create tilemaps in Tiled and implement with 2D Toolkit.
Cons

Con Bone hierarchy is not collapsible
When working with a complex skeleton, the entire tree is always visible. There is no way to hide bones under their parents.

Con Unity Middleware
SmoothMoves is not a stand-alone application. It runs entirely within the Unity Editor, and is not compatible with other engines.

Con Doesn't integrate with Unity's Sprite system
2D Toolkit provides a completely proprietary sprite implementation. Though it can be used alongside Unity's 2D systems, the two are completely separate and require different code to utilize.
