an engine faliure at 500 ft in the climb should not be too much trouble for the experienced pilot, remember a progressive flare will increase the time needed to lower the lever by several seconds. ok you got the lever down in time but then your faced with low RRPM but its a low inertia rotor so thats good because the RRPM will come back much quicker.
I would rather suffer a failure in a robbo at 500ft than say a much higher inertia machine like the bell 47, buts that just me