I have always been impressed with APC propellers so when I go my Phantom I decided to see what APC had that would be similar to the stock configuration of the Phantom. APC markets the the 8x4.5MR and 8x4.5MRP as multi-rotor props. I purchases a set and ran some tests. http://www.apcprop.com/ProductDetails.asp?ProductCode=LP08045MR http://www.apcprop.com/ProductDetails.asp?ProductCode=LP08045MRP The APC propellers are 2 grams heavier per prop than stock and stiffer. The APC props had to be reamed to fit on the Phantom. This stiffness might make them more prone to damage over the stock propellers, but this remains to be seen. Testing Procedure: Hover duration test of stock Phantom with GoPro camera installed at 6-8ft altitude until Phantom auto lands. Ran the test twice per prop set (twice for APC props and twice for stock props) using the exact same 2 batteries. Times were gathered using a kitchen time. Density altitude was calculated between test days. There are more precise ways of testing propeller efficiency. I believe the procedure that I followed offers a real world comparison of the differences to the stock configuration on real hardware in a real usage scenario. Batteries used: a pair of Mad Dog RC 2200mah 35c APC Prop Results: 60F degrees, 29.86in barometric pressure, dew point 52F Density Altitude = 323ft Hover durations: 9:45 and 9:33 Stock Prop Results: 59F degrees 30.00in barometric pressure, dew point 47F Density Altitude = 68ft Hover Duration: 9:49 and 9:34 Conclusion: Because of the very slight reduction in density altitude from one set of tests to the other, I would expect a tiny improvement in propeller efficiency from one day to the next; which is exactly what occurred. Also, since I am using a kitchen timer to time these tests, there is a bit of variability in the start/stop times of each test; i.e. my thumb may have been faster on the kitchen timer the second day. I personally do not think there is a significant difference between the prop sets and I consider the prop sets to be identical for all practical purposes.