I think mine is a Brother, and it's really easy to use. The stitches are fairly basic - straight and zig-zag with a few variations on a theme - and just 2 main dials to adjust; one for the stitch pattern that you want (match number to picture), and one for the width, if you're doing zig-zag. I don't know how much heavy fabric it can take, but I've put several layers through on it during my shoe-making course (best not to ask!) with no problems - I think it's more of a needle/tension issue, i.e. thick fabric, thick needle, tighter thread... Someone please correct me if I'm wrong!
Jo