AeroWeather is invaluable; PilotWiz and FlightPlan may be usefull, but CoPilot makes a perfect companion to AeroWeather.
It performs most tasks that the excellent Nav Box can (my usual flight planner) and some others Nav Box can’t.
Programming is quick and easy (once mastered that is, initially it’s not altogether intuitive) with an internet connection not needed. Rearranging destinations, waypoints wind, height etc. takes seconds only as does feeding in pre entered alternates – or for that matter, new waypoints.
Routes may be stored (but alas, not downloaded to GPS – but then, some might argue that this should be separate as a cross check.................
The database is comprehensive – airfields, VOR, NDB and a user waypoint database.
Minus points: No map – so user waypoints must be entered manually and my only real gripe, no VRP’s
Weight and balance and E6B calculators are provided.
With an internet connection, a CDI/DME is available, subject to the iphone’s GPS not having one of its periodic electric sulks
The main benefit (well to me anyway) is the ability to plan anywhere, anytime (“I’m on the train”) and to be able to amend quickly, if needed before, or even, during flight.
The help files are reasonable, but I had a poor response to an email question.
All very subjective of course, but it will only cost the price of a few minutes flying to check.