I believe you may be going for something like this (?): http://www.youtube.com/watch?v=X4nEF-7-HOA It's usually supersaws with an incredible square type lead over top. For the 'bipolar sound', I don't think you can achieve that through a synth, it's more the chord progression and the melody; that's...

Every time I mess around with a synth I end up getting some robotic heavy metal dubstep sound but I'm trying to get a more uplifting sound like Promises by Skrillex I love the bipolar element to his music. Any useful VSTs or advice?

I can get a nice wobble going, but I can't seem to figure out how to introduce my own signature sound, it just sounds generic.