As mentioned before a four blade will have faster hole shot due to more bite. It also affords better low end control. The three blade will usually have a higher WOT speed. In some instances the four blade will also increase the WOT speed over the three blade though it's not the norm.
Personally, knowing the type, number and conditions in which Dhadley has tested props, it would be hard to find more "actual" knowledge...maybe he'll catch this..
