iPad Mini Every Time
I fly with an iPad Mini with SkyDemon loaded and it's the dog's bollocks!
I also have an iPad Retina but it's a bit too big when mounted as it shakes about a bit too much.
I have used on the mini a clear case and have mounted a GoPro self adhesive camera mount on the back so I can lift it off easily. This is then mounted on a sucker cup with a short arm to reduce vibration. this is very useful when you are in and out of different helicopters.
I would highly recommend SkyDemon on the iPad Mini as you have everything in one place.
Last sunday I flew for a total of 4.5 hours and the battery died fust after landing. So thats not too bad? Obviously a power lead would have helped but thankfully it was not needed.
So to conclude Don't hesitate just go and get one!
Owain..