You might get more responses in the painting thread.
That said, it really comes down to personal preference and comfort level. I wou;d base my decision on color availability. Model Master has both an acrylic and an enemal line with a large variety of colors matched to specific standards.
Enamels are more airbrush friendly in that they aren't as likely to dry at the tip as acrylics, but they require thinner to clean up. The fumes can be annoyng if you use too much pressure. Acrylics dry faster and clean up is simply water. If you live in a humid area, a water trap is a must with acrylics since a sudden burst of built up water will mar the finish. The effect is much less pronounced with enamels.
W