I used FlyToMaps Watermap with the UK charts, very nice programme for seeing where you are on the charts, no route planning and I found that if I zoomed too far in near Kip marine, the programme would crash, must be a chart error at high zoom. I also had Imray charts, but didn't like the way you had to jump from chart to chart, on Watermaps the charts are welded together into one.
Never tried Navionics, two different apps were enough. Until I switched to an Android phone (Dohh!).
Someone on my boat tried it in the Tyrrhenian, 1st off, depth 30 in here no prob.... f* hell 10M ! ah, default calibration - feet.
feet !? there never has been any feet, it was fathoms then straight to M (maybe the yanks use feet)
Then set course for Porto Tropea, been there since 2nd century BC, ipad chart app - no sign of it.
Ok compared to paper charts at 10 times the price Garmin Bluechart is carp, and they are 10 times the price of this, which is really carp.
but you only get what you pay for, and that has to be good enough, any chart is better than no chart.
Even the pasta map of Italy on a tea towel is better than nothing at all
Three best apps for GPS navigation, (real time) are Navionics, Marine Imray Charts, iSailor. Or, (navigation real time), perhaps Navionics, iSailor, Marine Imray Charts. Best apps for route planning are iSailor, Marine Imray Charts, Navionics. I would recommend having at least two of them and one of them being Navionics.
Why not try out how you like the 'look' of all three by sampling chapter one of all three of my iBooks 'free'. You'll find them at routelist.co.uk. There are 4 others to sample, (which are perhaps not quite so good for route planning). I don't say anything negative about the apps I write about, (no names, no pack drill).