@TomY - Both programs do most of the same things, just differently. For example, the way they display tides and currents, weather and route progress is different, but they both do the same essential things. They both integrate ActiveCaptain info.
What I like most about Aqua Maps:
I find the User Interface easier to read and charts are more readable too. Also more customizable. They just updated the UI about a week or two ago.
Controls are logical/intuitive, particularly for manual route creation/editing and viewing/managing tracks and marks.
USACE latest survey data color shaded overlays are extremely valuable and useful - especially for inlets and channels in the Middle Atlantic and SE US where there are continuously shifting shoals
Integrates with Bob423 tracks including auto-updates - very valuable on the ICW
It displays AIS (via WiFi or Bluetooth connection to my AIS transceiver) in a clearer more informative way than Navionics or my Raymarine Axiom CP
It displays vector and raster (user choice) Explorer charts in the Bahamas, US government charts in the US
What I like the most about Navionics:
I like the way the current predictions planning control is done (better than in AquaMaps)
Automatic routing is very useful for quick estimates of "how far" or ETA of non-linear routes (I don't use those auto routes without checking them carefully - it makes some poor routing decisions). e.g. I use it for a running ETA to the next bridge, so I can slow or speed up to make a scheduled opening.
Sonar Chart - it has data (of unknown source or age) where the government charts and even Navionics official charts may lack detail.
I use it as a gateway to update the Navionics chart card in my chart plotter. If I update the app on my iPad then connect it to my Axiom chartplotter's WiFi it will sync charts, waypoints and routes, and tracks with the Navionics chart card in my CP.
PS - The newest iPad Pro M4 has made a major leap in outdoor sunlight viewability. It's worth the boat buck+ if you use it full-time at the helm like I do. It gets external AIS and GPS from my AIS transceiver over WiFi.