Flash illustration is more graphic (usually). While vectors can be slower to work with, a graphic illustration will take less time than a more realistic Photoshop painting. I suppose I could do a graphic illustration in Photoshop and see how quick that goes, but the thought of being stuck at one resolution for something that looks like vectors would pain me.
One thing I'm doing in Flash is trying different tecniques for rendering, such as:
- Starting with a rectangle and control-clicking to add points
- Drawing with the line tool, then filling, and finally removing the lines
- Drawing lines, converting to fills, then reshaping the lines (where necessary)
- Painting with the brush with maximum smoothing
One approach in Flash I haven't really spent time with is creating with the pen tool. After 19 years of Illustrator's pen, it looks similar but doesn't have the same functionality. Plus, using the above techniques has a more natural feel. I do use the pen for certain specific tasks that I'll cover another day.