Not tried the rest, but IMHO the Skymap IIIC is the dogs whotsits for VFR flying.
Don't have a screenshot from Scotland, but here's one from Spain showing high terrain, sea, VRP's etc. We's requested a transit of Alicante's airspace (the purple arc shows the boundary), and they'd asked us to route DCT to VRP "November Echo." Easily achieved from within the GPS flightplan with a couple of button presses...
