Ranked in these QuestionsQuestion Ranking
Pro Behaviours handled by objects
These features make it easier to create objects that can act autonomously with complex behaviors. This makes Paper a good choice for particle effects and game development.
Pro Object constructors
Elements all have the option of being created with a hash of properties which promotes clean, concise, and contextually local coding practice.
Pro Operator overloading
Pro Good for making games
Paper uses a frame based approach to rendering the canvas. This makes it conceptually easier to create objects with animations and behaviors that interact and perform with other objects.
Along with Paper's approach to creating and managing objects this makes Paper especially good for creating applications with complex behaviors with many elements doing different actions at once, and makes it a good choice for making games.
Pro Out of the box Node.js support
Fabric supports node.js, and has an npm package available for server side rendering with all the dependencies handled for you. This allows you to provide graceful degradation for image fallbacks to canvas or SVG content.
Pro Outputs to canvas and SVG and JSON
When it comes to format compatibility, Fabric is the best, with the ability to output to Canvas, SVG, and JSON. SVG provides backwards compatibility for older browsers, and JSON allows you to store rendered output for later use.
Pro Vector focused API
Drawing objects in fabric are vector focused, so everything is easily transformable. It makes it easy to create complex pathed shapes, add gradients, or filters. Although fabric is great for vector rendering, it also has image support as well.
Pro Great interaction with SVG, excellent coding
If you are about to customize the library to your needs, this is the project of choice! Great programming work!
Pro Good support for SVG multi-line text
Allows creating multi-line text that can even be interactively edited by user interaction.
Con Limited to single instance
The code is written in a way that everything is global and limited to a single instance, there is no clean way to use 2 separate instances in the same page
Con Not supported in older browsers
Paper.js runs on top of HTML5 Canvas, which is not supported in older browsers.
Con No front-end only version via Node
NPM package has major dependencies.