It's interesting, of all the classes of ball, I think I have consistently had less success with pearl particles than any other class of ball.

Occassionally they work for me but they are very touchy!
One should get more midlane from a pearl particle and less backend than it's reactive pearl cousin.

One's I have tried with various good success.  Core Power LRG, Shock Zone, Riot Zone, Track Freak out.  

The best was the Riot Zone(more particle arc) or Shock Zone(closer to a reactive).  Both were awesome unless there was carrydown and then they seemed to just disappear as far as effectiveness.

REgards,

Luckylefty