Well lets see...one reflector is a computer designed unit that maximizes reflected light. The other just lines the fixture....
On a serious note, PFO "new" mini pendant or the SLS ReefoptixIII+ are the way to go with DE pendants. Very similar performance. The ROIII+ is shorter and wider around with a slightly more square output, the PFO is smaller footprint but a bit taller and a more rectangular output.