Staedtler vs Identi-Pen marker for etching

I wanted to test out the markers for etching as well 

Staedtler red is supposed to be one of the best but I wanted to try the Identipen -

 As you can see the identipen worked better with the ferric - but I am going to do further testing just to be sure

Using the pen is one thing I need to do so I can make my copper beads and ensure the etch will not eat through the marker