Paper [1] quotes the system's efficiency at 1.2 mN/kW.
Hall thrusters, a propellant-throwing electric engine, perform at 60 mN/kW. Non-propellant systems like light sails, laser propulsion and photon rockets perform around 0.0033 to 0.0067 mN/kW.
If it works, this isn't how you get people to Mars. It's how you move cheaply freight (and probes) around (and out of) the Solar System.