AvChecklist perhaps is actually the most advanced aviation checklist for iPad devices.
Principal features:
-Easy use and quick access to the main functions.
-Control and monitoring of the verification activities.
-Persistence context screen between sessions.
-Different behaviors according to the phase of flight.
-Pilot checklist in addition to the aircraft checklists.
-All checklists are editable.
-Speech capability
-Allow sharing checklists by email
-It has utilities to check and uncheck in block.
-Allows you to create different types of items groups in each section.
-Copy checklists capability.
-Supported landscape and portraid screen orientations
Definitely an intelligent way to make your flight safer.