iPhone (10000 programs)

Pros: Accurately emulates pen or paper feel. Lots of different notepad themes. Integrated with DropBox and Evernote. Share instantly via social media.

Cons: Requires a stylus and tablet for best results. No PDF import or export support.

Pros: Multiple game modes. Diverse character classes. Multiple weapon and vehicle types.

Cons: Needs more maps. High battery drain.

Pros: Simple interface. Easy-to-understand lessons. Helpful next step activities.

Cons: Mainly introductory material.

Pros: Dozens of puzzles to solve. Two game modes. The jungle scenery.

Cons: No originality. Few levels compared to similar games.