I love Son of Beast. When i ride roller coasters i like to actually feel them. It is the tallest and fastest woodie so obviously with that comes the roughness factor. It doesn't bother me at all. I have heard that much of the blame is to be focused on the trains. They are poorly designed, from what I have read.
I have no idea how many wheels the Beast goes through in a year. I don't imagine it being much more than any other coaster though.