The surface finish of the coverstock will have huge impact on the ball's reaction, and the core design and RG numbers will also have influence. so the coverstock type is only one piece of the picture.

Basic reactive coverstocks come in solid an pearl form (and some as a hybrid mix of both), the latter having mica additives that enhance the ball's length, and pearl covers tend to be suitable for lighter conditions than solids - relatively! Some pearls are very strong, so you cannot generalize.

Particles are additives that are added to the reactive base, that act like spikes (in the case of hard material) or to enlarge the ball's effective footprint on the lane (soft additives), and their primary objective is to enhance friction in the oil and smooth out the overall reaction. Particle balls tend to hook earlier and more even than pure reactives - but do not necessarily show more overall hook. They also tend to need more head oil.

Modern reactive coverstocks are so porous that they seem to render the paricles' extra traction in oil obsolete, but these absorb lots of oil and need frequent maintenance.

Hope this helps - it is very vague and relative.
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DizzyFugu - Reporting from Germany

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