Contestant 1: LayetPaint\Contestant 2: SketchBook\Contestant 3: Skitch
Version 1: 1.2.13\Version 2: 2.0.3\Version 3: 2.0.6
Feature 1: Easy to use, supports layer operations, actual drawing effect is quite good\Feature 2: Variety of brush types, supports layer operations\Feature 3: Can sync directly with Evernote, functions are relatively simple, more suitable for annotations
Engineer summary: SketchBook, a must-have tool for mobile drawing
