My question, is EVERYONE concerned about the last little gram of thrust or efficiency? Unless you are entering contests all the time I don't think there will be a whit of difference between using a 2,3 or 4 bladed prop. Many (note I didn't say all) of us just like to get out and fly. If my airplane goes a tad bit slower on one prop I probably won't notice. SO I think the factors in using multi-bladed props should be, 1. Do you need to increase your ground clearance? and 2. Do you like the looks?
The rest is all fluff.