No dust is very important when working with cement fiber products! Last thing anyone needs is silicatosis.
The fiber shears do work great, But I still wear a mask when working with it.
If I did more work with it, I'd spring for an air operated shear.
PacTool International makes good tools for working with it.
Here is where I bought some of mine from:
http://www.northwestpowertools.com/t...cificshear.htm
I know this stuff gained popularity in the NW after the LP siding debacle in late 80's/early 90's. As a result it is pretty much all you'll find here, with the exception of the "low rent" housing projects which still use vinyl.