Pixi Particles vs PopcornFX

Pixi has an editor available which makes it super easy to create and customize your particles. The editor exports your settings to a JSON file which you can then load into your project for the Pixi Particle library to use.
You can check the editor out here.

Pixi is a particle system library built for the PixiJS library (a WebGL renderer), which makes it ideal for a browser based game.

Pixi allows for importing custom particle images, meaning you can create your own graphics.

Pixi's interface is just a simple web page. All of your tools on the right, and your preview in the center. Nothing is buried or hidden in menus, so finding the variable you want to change is incredibly easy.

Aside from the editors within the engine plugins, PopcornFX also includes an external editor which allows the user more freedom with their particles.

PopcornFX, unlike a lot of other particle effects tools, is editable from a tree (a lot like layers in Photoshop) rather than a set of nodes. This removes a lot of complexity from editing your particles, while still retaining all the control you have with a node system.

PopcornFX comes with plugins for both Unity and the Unreal Engine, which cuts down on the workload of generating particle systems by allowing you to do them in-engine.