This app was mentioned in 1 comment, with an average of 1.00 upvote
I have a Samsung GalaxyTab 2 7.0, which so far has never let me down GPS-wise in about 90 flight hours. I use VFRnav, which covers most of Europe with airport/navaid/VFR-reporting-point databases, airspace data and OSM-derived maps.
I usually have it connected to the aircraft power supply, and have it mounted on a suction cup; it normally acquires a GPS-fix within a minute after turning it on.
It's no longer available new, since development has gone on, so I can't speak for its successors.