I have talked about this many times, basic idea is any resistive heater uses the same energy to heat a room, however if you need to switch on earlier or if there is a hysteresis problem this can also effect the energy used to a small extent, only if you can modulate the power used can one trim the heater to regulate without any over shoot, this is the whole idea of gas heating with OpenTherm and the like, using the TRV you can gradually reduce or increase heat output.
With electric in the main looking as switching on/off and the time between each on, the ratio is called the mark/space, but it could switch on every 2 minutes or every 2 hours, depends on the losses from the room, and method of switching.
With solid state switching one could switch on every minute. The heater could be on for 20 seconds and off for 40 seconds. But with mechanical switching the contacts would not last long, so not likely to be less than 6 minutes with 2 minutes on and 4 minutes off, but more likely 20 minutes on and 40 minutes off, the on/off or mark/space ratio is the same, but the sine wave of temperature would be very different.
The hysteresis can be damped down by heating oil or bricks main with a high iron content, or a larger room, or reducing loses. So if we said with my living room with x losses and x area which is the best heater, one may be able to say this is the best, but without that it is simply an unknown.
However the safety aspects are not unknown, we have loads of cases where paper has fallen onto a convection heater and caused a fire, so large firms having had loses due to fires have stipulated oil filled radiators to reduce the chance of fire.
Costing 30 units to heat or 31 units to heat is neither here or there, it is safety that matters, and the oil filled radiator in the main is safer.