Being a full scale pilot as well as a beginner in R/C, I can tell you this... ALL of the fastest and most maneuverable full scale single engine aircraft run three bladed props: V-35 and A-36 Bonanza, Cessna Centurion, Piper Malibu Mirage, Piper Lance, not to mention all the higher end Aerobatic craft like the Sukhoi, Edge, Extra, most of the Pitts, CAP, the list goes on. i've flown a tad over 3,000 hours, and around 1,000 hours of that in 450 and 600hp B model Ag Cats, and the ones I've flown with three blade prop conversions ALWAYS performed better... higher cruise speed, lower fuel burn, less noise, and a shorter take off roll with a heavy load.
one of the fun things about RC is that lots of things don't scale. the size of molecules, time, and wind all remain constants throughout different sizes of RC.
in particular, just because all of the high performance craft use three bladed props doesn't imply that 3 blades are better. what if they all are tail draggers? does that automatically mean that is more efficient? the 3 blades in those situations is probably a design choice to get a prop to match the airframe, where a 3 blade fits and a 2 blade won't.