Putting synths through pedals/amp sims is a great idea. Something I do a lot of anyway...'dirty' sounds are very in fashion at the moment in the trance/electro/industrial scenes. Boys Noize/Deadmau5/Justice etc.
Of course there is nothing to say you have to dirty them up, used subtly they can take the rough edges off a sound or help bed a synth sound into an arragement, esp one that uses other miked up instruments.
Can't wait to get my hands on OS4 tbh!
