Paint Pen

I have used one on my TJ and it works great. Has a pen, touch up brush, and clear coat all in one device. I keep one in the glove box.
 
What would you say the largest scratch or chip is that these would cover effectively?

I have some fairly large gouges or scrapes out of my doors. Some down to the steel.

I have been looking at those pens i posted above. But it sounds like oem may be better(?).