ZeusDraw has enormous potential. Very intuitive for making quick strokes and simple shapes. The individual tools are easy to get the hang of, but the pen tool takes getting used to for longtime Illustrator users. ZD has a unique way of manipulating Bezier curves that might frustrate some users. Personally, I draw much faster with the Illustrator pen tool, but that's because I've been using Illustrator for years and I'm used to it. I think ZD's way offers many benefits over the old and dated Illustrator way and it's worth getting to learn this alternative (arguably superior) method. Additionally, ZD is stable and has a very small footprint (less than 80MB of Real Memory after several hours on my system); a welcome change from the bloated, crash-prone Adobe Illustrator.
The menus and palettes could be better organized. ZD lacks the ability to tear off and dock frequently used palettes together like Illustrator.
GUI is way too small for large monitors and high resolutions.
GUI looks like it's stuck in OS9.
Needs proper color mixer palette. The current color palette is not intuitive to use.
Needs proper brush palette. The Brush Library palette is especially lacking -- non-adjustable size and way too small, even for the default brushes, which means you must scroll through your brushes.Ugh.
No context menu items. Boo!
No text on a path.
Email artwork only works for Mail and Entourage; no PostBox, GyazMail or any other app.
Too expensive, all things considered. A lower price would encourage wider adoption and lead to a better app in the long run.
Overall, I think ZeusDraw is a great app with enormous potential. Once it addresses the issues on my cons list, it will no doubt be a strong contender for people who are looking for an alternative to Illustrator and the late, lamented Freehand (R.I.P.).