In Illustrator, creating a uniform, yet random-feeling busted look can be challenging. I've been trying Effect > Texture > Grain (Horizontal & Vertical), then rasterizing at 72dpi and then live tracing back to vector.
Edit: lots of people have asked me about this so here's a few more details concerning this tip.
1) When applying the Grain Texture, set your Intensity to 82ish and your Contrast to 100.
2) When live tracing, try these settings and tinker with the Blur and the Path fitting. Maybe mess with the Threshold.
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