Should I use a 3-Blade or 4-Blade propeller?

Theoretically, a 3-blade propeller should always be more efficient than a 4-blade. However, in the past, two big issues have prevented the 3-blade from taking the lead in popularity. The first was a lack of manufacturing precision, which commonly caused 3-blades to vibrate more than 4-blades. When significant dimensional variation exists in a propeller, vibration is generally more noticeable in a propeller with fewer blades. The second reason for the 3-blade disfavor was an almost certain loss of blade area in the transition from four blades to three. Consequently, even though top-end gains were achieved, performance expectations on the low-end were diminished.

Through the implementation of precision manufacturing and design improvements, 3-blade propellers are receiving the reputation they deserve. Manufacturers are consistently holding tolerances never before achieved in propeller production. This accuracy makes most 3-blade propellers incredibly smooth. In addition, the blade area of some 3-blade propellers have been expanded to equal that of 4-blades. From an awesome hole-shot to an unmatched top end, and smoothness throughout, some 3-blade propellers exceed most expectations.

It should be noted that this choice might still be mildly influenced by application, because it is possible that the most perceptive users might be able to detect slight differences that cause them to prefer one prop over the other.