ORIGINAL: eddieC
For our models, there's little difference.
From a design & efficiency standpoint, the fewer the blades, the better. The primary reasons for number & diameter of props on full-scale is prop clearance and keeping prop tip speed below the speed of sound (big loss of efficiency).
Then why does a large plane like a C-130 with absolutely no ground clearance problem go from a four blade prop to a 6 blade prop? Reason because the 6 blade prop has lower tip speeds, is more efficient (see lower tip speeds),bites thin air better, and has higher high speed thrust.