This one's for Millsy really.
I know you are looking for some software to do Particle Effects and have been looking at Particle Illusion. Did you know there is a new plug-in from the well-respected plug-in people, Trapcode
Take a look and watch some of the demos. It looks pretty good to me (I like the stick, slide and bouce effect).
The benefit of course here is that you could do all your Particle Effects work from within AE and not have to export to an external program.