iPad's (even better the iPad mini!) with Jepp subscription. Updates at least every 28 days. We'r using it as the backup charts for our onboard e-charts - screw the paper charts (besides from the enroute charts and "fold out" terminal charts!
I prefer Goodreader before the iBooks app - just because its easier for updates and also, making notes is not that good with iBooks as with Goodreader.
Good luck with your choice!
