Natural Light Shading: Using the same logic as Trapcode's Lux plug-in, the particles are responsive to AE lights with organic and natural light fall-off.
The advanced shading options are features unique to Particular.
Performance
Like any particle system, the more complex your comps are, the longer your render times will be. That's a given. So what interests me is how functional the plug-in would be when I got into creating complex effects. Trapcode provides a motion preview option in addition to full rendering, so you can quickly render out a comp that shows the gist of your particles behavior. Also they offer a range of particles that don't respond to Depth of Field. This is cool because even though having particles with depth of field is really cool, sometimes your really don't need to see it. It's nice to free up the processing power by being able to choose a non depth of field responsive particle.
The Organic Lines preset is one of the many included presets that makes purchasing pre-fabbed motion graphic elements unnecessary.
Value
At $399 for new users, Particular 2 is a spicy meatball to be sure. (Previous users only pay $99 to upgrade.) For current Particular 1.5 users, the upgrade has enough useful new features to make it a great deal.
Making your AE light the emitter means your particle will become the light source for the 3D scene.
It is difficult to say how practical this $400 plugin would be for the microfilmmaker crowd. True, Particular 2 is the creme-de-la-creme of particle systems, but will it make your films look better? It really depends on how much you need particle generation in your films. (For explosion augmentation or adding fireballs to your fantasy world, a little creative use of Particular can go a long way.) I would recommend first becoming a master of Cycore's Particle World, and determine the value from there.
