If the 2 units in question were the same capacity and physical size, their efficiency (BTU delivered per KW consumed) would be the same.
If one system had a physically larger evaporator or condenser coil but the same BTU capacity, that unit would be more efficient because that unit would have more surface area to reject the heat and thus deliver more BTU per KW consumed.
A ducted a/c system would take longer get a space to temperature over a non ducted system if the ducted systems supply and return outlets total free area was less than the non ducted system (assuming they were both the same capacity). We’re all the a/c outlets opened 100%?
If that is the case, it would make the non ducted system SEEM more efficient because the trailer cooled off faster.
The benefits of a system that takes longer to cool off a space are this....
1. The longer a system runs between cycles means that more moisture is removed from the space. The drier the space, the better the comfort.
2. The fewer times a system cycles (turns on and off) to maintain a set point in an hour means less wear and tear on the internal components of the a/c which should increase its life.