System S+U needles

In my experience, these needles are better suited for saddle stitching compared to John James needles for two reasons:

Blunt round point needle head 

Doesn't easily catch leather fibres when pushing through the stitching holes on your workpiece. 

The blunt rounded tip doesn't scratch and damage leather surface when you're being a little careless.

Channeled thread hole

The recessed thread loop allows the thread to sit into the channel, reducing the girth of the knot. This allows the butt of the needle to pass through stitching holes easily.