Actually, it isn't that difficult to learn.  The Poseworks site has a number of tutorials (which, you may want to check out prior to purchasing) that help you pick it up.  It can create some really astounding looking effects.  And, if you are into animation, all can be animated - rolling fog, clouds, gun muzzle blast, etc.  I think it is well worth the money.  But, check out the tuts first.