Dupli-Color should be awesome if for no other reason than it's a Sherwin-Williams product
Have you tried it on GI Joe?
Honestly, my Testors Model Master Acryl paint doesn't chip as long as I gently dremel the fronts of the elbow joints. Of course I don't bash my custom figs around either, but I've dropped em a few times without any damage.
Dropping is one thing, but moving elbows, knees, shoulders, etc. are small movements that will remove any other paint coat from the factory paint. Rit dye is a cool process that goes into the plastic. But other enamel or acrylic paint just go over the figs and won't follow the movement.
That is why I'm looking for a strong paint that will stick to it's surface... like a car paint...
Martin