Can't speak to flying in Iceland, but, FWIW...
In the US pretty much the top of the heap is either:
a) Foreflight or Garmin Pilot on iOS
or
b) Garmin Pilot on Android.
I have some religious objections
to iOS--er--more seriously I use my tablet for a LOT more than flying and prefer the Android ecosystem to iOS, so I have chosen Garmin Pilot on Android. However, to be completely objective, Garmin develops for iOS first and iOS users get the best stuff first, period. If the only thing you are going to use your tablet for is flying (in the US), iOS is the way to go.
The primary discriminant between Foreflight and Garmin Pilot is whether you live in a Garmin-centric cockpit environment or not. If you have non-Garmin sources of ADS-B traffic and weather, you pretty much have to go with Foreflight, as Garmin only supports Garmin.
Since I control my cockpit environment, I selected a GTX345 to fulfill my ADS-B requirements. I will say that it is the cat's meow to have traffic and weather (TAFs and METARs, not radar--I'm VFR only
) on my tablet with Garmin Pilot.
aa