The guy in this video is also using a homemade snath.
You can see how it would be much faster than a string trimmer.
http://www.youtube.com/paulwheaton12#p/u/0/0mqFl86BOck
Makes me want to get mine out now....
Here's the West Country Scythe Competition 2010: Scythe v Strimmer. I really liked the third and fourth heats.
http://www.youtube.com/watch?v=Nx_PDiEjW_E (http://www.youtube.com/watch?v=Nx_PDiEjW_E)