Still, I'm betting that the people who enjoy Black Ink really, really enjoy it. Apparently the program even downloads puzzles "on the go," so if you're not already a crossword fan, maybe it'll turn you into one. The new version adds a menu item for zooming in or out of puzzles, a few interface tweaks, and "correctly-solved detection for puzzles with multi-character answers." I never knew those existed, but there you go.
Black Ink is available for $24.95 over on Red Sweater's site.