if you want something dedicated to heavy synth i would go for the ashly sc-50.
it is a "mojo" piece. it distorts slightly and pleasantly, changes the frequencies. great thickening device. i run all my synths thru it, and am very happy. it is a tad noisy if you abuse it. watch that gain knob!
do a search on it on google groups. people love the shit out of it. especially for lead instruments (which i would classify synth as).
$99 right now at music go round.
oh and it works pretty nicely for drum machines too! sort of a two trick pony with them. (if you get the sc-50 with the limiter button, otherwise it is a one trick pony)
when you push the box with the limiter circuit on, it does all sorts of crazy thing. the compressor is a bit tamer.
You're kidding, right????
