I did mention it is usually best to rasterize your font before applying the layer style - in most cases this is a good idea.
Here's a side by side comparison of the Medieval font, the first is straight up font, the second has been rasterized and rippled:
If the first one suits your purposes, excellent! It's a nice effect as is, and subtle, but working at smaller sizes it could get lost. Experiment as you see fit.
An additional note, some fonts do not require the rippling anyhow. A lot of the grunge style fonts already have the rough edges we're after, so you can just work with them as is - for example, this font is called Webster: