There are some physical characteristics of the three versus the four blade prop that must be taken into account. One physical difference is total surface area between the two props which will increase drag thus reducing top speed but that added surface area allows for faster acceleration. There are other elements to consider such as diameter and pitch that needs to be optimized based on the power curve.
I originally got a four blade prop thinking I need a good hole shot for my size but I realized after having the boat that I don't utilize the full range of throttle at startup so a three blade would work fine. The prop wash is more than desirable at 36-38 mph where I ski and it would be interesting to see how a three blade would affect it.