I have a few of the Testor paint pens I got for birthdays, christmas, etc but I never like the feel of them. I thought the tip was a little too wide for the touch up work I tired them on. And I never thought the paint flowed well enough to use on a larger coverage area.
What i do like the Sharpie Silver ink marker. It looks similar to a shinny aluminum. I use it often for touchups and small area detailing. I have used it to simulate paint chips on aircraft wings & props.
-Jamey