Dennis, I do not know what exactly they call "efficiency" but if they say that the wider blade has better efficiency, then I am on doubt
3 blade prop has 3 blades making drag, but also 3 blades making thrust, so the efficiency is very similar to 2 blade of the same blades. However 3 blade prop can be replaced 1" larger 2 blade prop of the blades which are longer, but has aproximately equivalent width, and in that case we WILL come to better efficiency, because drag of blades when prop makes lot of thrust is dermined by induced drag on its tip and that is determined by aspect ratio of the blade. That is reason why multiblade props are typically less efficient, but if we use prop of the same aspect ratio, we will have similar efficiency, and if they say the wider blade will reach better efficiency, then it is hard to believe
... may be only some kind of troubles with RE number can make 2 blader better, but I think we have those props large enough and rotating somewhere at 10 000 what is much higher than r/c flyers use to do with those plastic APC, so I do not think it is really a problem.