The people who probably know best are the pilots and office/dispatch staff. Don't miss an opportunity to hear from them.
Depending on the type of operation and aircraft equipment I'd be concerned about iPad battery autonomy, dirt/waterproofness and unauthorized use in tricky weather conditions. For less than 100$ you can plug a quite precise GPS that's much more responsive than the built-in GPS (I've seen it work flawlessly in an airliner in cruise). The temptation to use the iPad for navigation would be significant.