What Prop ?
This will end up being a popularity poll based on the props used on the most common plane sizes and won't give you or anyone else any useful info.
My current "favorite" props are a 27x10 Menz and 17x10 APC... mainly because they are on my two favorite planes. It has little to do with the performance of the prop.
The "best" prop I have flown with was a P-tip prop made by Prince, but they are bloody expensive, like several hundred dollars a prop. For that reason, I use the APC and Menz, even if they technically aren't my "favorite."
I also like Zingers because they are real good for mixing paint.