The bassballs is worth a shot. It's a love-it-or-hate-it pedal though, and (IMHO) it gives better results when you forget it's an envelope-following filter and put it later in your signal chain instead.
Although at low sensitivities it's really, really nice as a filter (well, two filters I suppose) for slap playing.
It's weird, I don't see much love for the bassballs here but I can't seem to get mine off my board. I think bassballs to me is like overdrive to pretty much everybody else around here. Except I don't really use the overdrive switch on my bassballs...
