I agree, Sky Demon seems to be way ahead of all the rest.
We used it for a VFR trip to Hungary and back in the Summer. One of our group had Sky Demon on an iPad and became the leader as the software with weather, Notams, restricted airspace etc. allowed us to thread our way through very complex airspace.
Some of the flightplans would have taken hours the old manual way with charts and Garmins. Skydemon took minutes and even filed the flightplans.
I am thinking of an iPad mini as I can't get the full iPad in the cockpit.
I know the Android tablets are very good but there just doesn't seem to be any software like SkyDemon for them.