I have been using a class 2 EFB in 121 ops for 6+ years now, so permit me a few observations on the subject.
1. Not having to do revisions is nice, but the down side is you essentially get a new set of manuals every few weeks. All your margin notes, tabs and other crutches are gone. Yes, there are annotation capabilities in PDF files, but you will be getting new files every revision so they won't stay with you. You can make stand alone notes, but after a while you will be using your maybe correct, maybe out of date notes instead of the real manuals. Then come check ride day you won't be able to look something up. Good luck with that.
2. Not having a paper MEL just plain sucks. It takes longer to look up something in a PDF file, and you are more prone to miss important information by scrolling past it. Sure there is a search function, but did you spell generator right this time? Is it fire bell or fire warning? Computers are literal, humans not so much. No reaching for the MEL book accepting a bird and thanking the last guy for tabbing that MEL reference for you with a piece of his dispatch release.
3. Company issued vs personal device: We have bolted on EFBs in the flight deck and the company provides us with the files to put on our own devices for study (and computers in the crew rooms for people "too poor" to buy their own). I like this approach, use the company device while working, have no privacy issues for off duty use.
4. Forget using a tablet GPS in the cockpit. Most consumer GPS units won't work above 100 kts, and very few can get a signal through the windshield heat. I know, I've tried. For some reason the FAA has a real issue with moving map in flight for 121. They barely allow it for taxi.
And a question: To use an EFB in critical phases of flight, it must be secured. How are you going to do this with individual vs ship devices? Knee boards like back in flight school? Is everybody going to use the proper restraint all the time? Somebody is going to forget it on an FAA line check, and guess what will happen! You will be the reason for a company wide memo to not do that again.