When comparing Phaser.io vs Duality, the Slant community recommends Phaser.io for most people. In the question“What are the best 2D game engines?” Phaser.io is ranked 13th while Duality is ranked 27th. The most important reason people chose Phaser.io is:
There are plenty of great learning resources available for Phaser.io.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Good tutorials, courses and books
There are plenty of great learning resources available for Phaser.io.
Pro Animating is easy


Pro Very fast to develop with
If you're browsing Slant, you probably already have a JavaScript enabled browser, which is most of what you need to get started learning JavaScript. The requirement to run a server locally on your computer while developing might make things a little more difficult
Pro Super-simple loading of assets
Pro Support for Arcade Physics, Ninja Physics and p2.js
Pro Great community resources
Pro Easy to learn
Pro Excellent tools for sprites
Pro Built-in Arcade Particle system
Pro No install required
All you need to do is attach Phaser script to a HTML page even without installing any extensions.
Pro Very active development
This is one of the most developed frameworks right now.
Pro WebGL and Canvas rendering modes
You can choose WebGL or classic HTML canvas element for game rendering.

Pro Open source
The full source code is available on GitHub, where the framework is actively developed. All of the editor, core and plugin code is written in C#.

Pro Great editor
Duality includes a powerful visual editing system that can be used for previewing, integrating, editing and testing game content.

Pro Live reload of code and assets

Pro Very extensible
Because both Core and Editor are completely plugin-based, Duality not only incorporates a clean and modular design, but is also very extensible - even if it wasn't Open Source. In fact, most of the standard editing capabilities comes in form of Editor plugins.

Pro Built-in physics and lighting

Pro Friendly to version control systems
It can be configured to serialize all data in a text-based format, which has been structurally optimized for version control systems.

Pro Used in commercial projects
It has been used in a production environment without burning the place to the ground. Supposedly artist-proof editor workflow with an API for tailoring the system to fit your team.
Cons

Con Poor performance
As long as your map is not larger than 600*400px, everything is fine.
Con Visual Studio required
To have possibility for scripting you have to download entire Visual Studio and spend 10 GB of free space