Not really, not yet anyway. My company just got them, and it is WONDERFUL. Mostly because a full US ship-set of JEPPS takes up all the room in your kit bag, and lugging them around does a number on the back over the years. Plus the update is a tap of the screen vs. hours pulling and inserting onion skin sheets of paper on your days off.
I don't know the exact numbers, but I'd say it is well less than 25% of 121 carriers are EFB.