I couldn't use this as is, unfortunately.
I'm not really into graphics editors and enjoy writing code much more. The goal for me was to simplify creating wireframes with code by having a set of predefined "sketchy" styles and several ready-to-use UI widgets and shortcuts for common layout patterns/classes so I don't have to create and type them in from scratch for every new wireframe.
This already saved me a number of hours as I'm creating some wireframes on how a future product at my company will look like.
This is exactly how browsers render SVG filters currently, and it looks the same edgy on my non-retina Mac too...
And that's why I've included a separate script (make-screenshot) which uses PhantomJS and ImageMagic to render high-quality hi-res version of your wireframe. I used that to produce screenshots for github readme.
Another option is to try zooming-in a bit in browser, like to 125%, this way it looks a little bit better imho.
I agree with other commenters, it could be a little less wavy, but to be honest I don't care much if this works, after all its just a wireframe.