Most of these flying taxi designs seem to be multi-rotor, and I'm not sure they are more reliable. Even a single-engine helicopter can autorotate, these multi-rotor ones generally can't (maybe they could) and depending on the rotor configuration, can't fly with one rotor out of action. For example a typical quadrucopter with one motor out just falls to the ground.
EDIT some discussion here: https://aviation.stackexchange.com/questions/37360/can-a-pas...