From seeing how AS issue their dig-e-players, expect the crew to spend half an hour giving these out, then they start the drinks service then food. Effectively it just delays everything while sorting the technology. And then they have to get them all back before approach. Oh, and there are some swaps because the batteries are flat. Sounds great, but I'd want to be convinced ....
Oh, passengers should find the ipad in their seatfront pockets upon boarding - and the ipads are fitted with an external battery that supposedly lasts up to 20hours.