It largely depends upon many factors what are you going to be doing with it. For a scale gently handled model acrylic is fine for something to be handled roughly then enamel ( or cellulose ( if you can find it)). Just remember that the surface your painting on counts cellulose onto enamel will "pickle" acrylic you can paint onto just about any finish. Seal it all with an acrylic varnish.
"that's not a bug its just an undocumented creature."
Sir Terence David John "Terry" Pratchett, OBE (28 April 1948 - 12 March 2015)