All of my clients prefer to file paper returns.  If they owe, most of them prefer to send paper checks.  Different strokes for different folks.  I explain to them that I don't believe my professional ethics allow me to agree to unannounced inspections of my files by armed IRS agents.  Also, that their data is not sent to IRS, it's sent to a third party who may be located overseas and in any case has no guarantees against hacking.  I can charge lower fees because I don't need to do all that data entry that EF requires.  But then, I waste a lot of time enjoying all the stories posted here by preparers who lose the battle with the computer.