Don't know about the (8-rotor) eHang, but the 18-rotor Volocopter remains fully controllable with 3 rotor failures (or more, if they're benignly distributed), and has a ballistic rescue chute in addition (which is hard to fit on a heli).

(Of course, you need a certain altitude for the BRS to kick in successfully, so low-level hover is a risk, just as with a helicopter.)