I have painted a lot of plastic figures with the art & craft type acrylic paint that comes in about 3" bottles. I mostly use satin finish and they look great. However, it takes several coats depending on the color. Consequently, this becomes very time consuming and tedious, except for the easy brush clean and lots of color choices. The Testors oil paint probably covers better with fewer coats but also has fewer color choices and requires solvent brush clean.
The right small brushes make a big difference too.