Here are my 2 cents on props:
A) As stated above the ones from the factory do a good job
B) The Factory are an excellent "compromise" between efficiency, cost, rigidity, and flexibility
C) If you push your priorities to one of the above areas you have a loss in the other areas (It's a balancing act and if you add more to one you take away from the others in some way).
D) If you add more rigid props your likelihood of damaging other components further inward is GREATLY enhance. On one of my CP R/C helicopters I wanted to add Carbon Fiber blades to get a firmer "bite" in the air. I got exactly what I wanted but any time I had a blade strike instead of spending 10 minutes to replace $10 blades I was spending hours replacing components further into the aircraft ( rods, gears, shafts, links, grips etc) that ended up costing more than the factory blades. Basically if the blades are tough/rigid that energy is transferred deeper into the aircraft. I like having a designed point of failure that is cheap and EASY to replace.