Downloading Particle Illusion Standalone is pretty easy. All you need to do is go to the website, register for a free BorisFX account, and then download the installer. The first thing you should do after you run the software is go download the Emitter Libraries so you can get a big library of presets.
Using the software is pretty easy. You can pick a preset from the library and preview it on the upper left pane, and then click anywhere on the right viewport (the "Composite View") to place the particle emitter. After you've placed an emitter, you can move it or resize it until it fits your needs. You can tweak the particles by modifying the properties of the emitter in the Controls View. There, you can change different settings like velocity, size, life, opacity, color, etc. You can also animate these settings, giving you more control to create what you want.
Particle Illusion Standalone also includes a variety of particle shapes to choose from if you want to change a particle's default shape (or "texture" if you want to call it that). For example, if you are generating some stars, you can change the star shape for something else. If you want a custom particle, you can also import your own pictures as shapes.
Rendering is very straight forward. Basically, you just need to select your format, and you are done. Unfortunately, you can't export as image sequences, since you can only choose between MP4 or MOV. If you choose MP4, you cannot include the alpha channel in the movie file, so you would need to render the alpha separately. On the other hand, MOV lets you render the particles with straight alpha or premultiplied alpha, making it very easy to composite the particles into your video project.
I don't have Quicktime installed on my Windows system, so I cannot use MOV files in my projects. However, I tried the rendered MOV file in iMovie on my Mac, and, just like I expected, I got the premultiplied particles to composite on top of my video.
Particle Illusion Standalone is a very nice and easy-to-use tool to create particles for your projects. Being GPU-accelerated, it lets you work with complex projects without any issues and the rendered movies can be easily imported into your projects.
The only thing I don't quite like is how you cannot export as file sequences, but MOV files will work fine in most cases. If you want more power to create amazing effects, you can get Particle Illusion as part of the Boris Continuum suite.
Get Particle Illusion Standalone at borisfx.com.