If you think about editing in Paint Shop Pro, then I assume you do not understand what vector images are:
http://en.wikipedia.org/wiki/Vector_artFirst read this
Arcade art is mostly vector art, and you don't paint in it, but you pull on grips that form shapes and lines.
Inkscape does handle vector and PDF, but I think it does not compare to the pro aps. On a scale from total suckiness to total awesomeness in basic vector editing going from 0-10 I would put Inksape at 3, Coreldraw at 5, Illustrator at 7 and Freehand at 9. Freehand's paste-inside function is 4 points worth by itself already (you will need that very much in arcade art). Sadly it is discontinued as Adobe bought Macromedia and still believes Illustrator is better. But heck, version 10 runs awesome, even on Macs with Leopard.