Artists will find this simple sketchbook app limited. Ideas is basically just a white canvas and single brush, adjustable in size, opacity, and color. But when you need to explain something visually or sketch out a sudden idea, it's way better than the back of a napkin.
WIRED Brushstrokes automatically smooth out. Vector-based approach means clean zooming. Can doodle on top of photos.
TIRED Missing basic drawing tools, like color fill. Can share via email only as a PDF.