My ZeusDraw review has been updated, as Robert Clair from Chromatic Bytes contacted me to let me know I was wrong about a couple of ZeusDraw’s features. Sorry Robert!
ZeusDraw can in fact open .EPS files, you just have to import them as .PDF files first and then convert them to objects. The color palette in the Apple Color Picker also works, the values in the steps column just have to be changed.