Except for French stitch all those listed above have one thing in common, viz. that they slope diagonally across the threads in the front of the canvas, therefore ensuring that it is well and truly covered—provided of course that enough wool has been used in the needle.
Stitches that follow straight lines parallel to the threads of the canvas nearly always show the canvas and are therefore unsatisfactory.
The reason that French stitch is adequate is that in the working every hole is entered four times, the stitches are tied down very tightly, and packed so closely together that the canvas is of necessity well covered.