If it's at '1' then it prints the infill on every layer.
no it doesn't. It's on 1, it won't let me set it to '0' :-)
It still leaves gaps between the plastic strands. There is no setting where it forms a solid infill matrix.
Yes it prints infill on every layer, but it prints alternate squares, hell it's not even much good for compression.

If I print a part at 10% infill with s3d i can easily snap off any protruding parts with my fingers. I print the same part with the same settings in makerware I need pliers and a hammer. And that's because makerware forms a solid mesh within the shell.
s3d just won't.

I don't understand why it won't. But trust me - it won't.