Most engines are shipped with three bladed propellers, but more and more are being offered with four bladed propellers. Four and five bladed propellers offer increased torque and enhanced holding power at higher trim angles. Four and five blade propellers are purported to reduce vibration, and that makes sense to me, because a four bladed propeller is more symmetrical than a three bladed design. Top speed is said to be reduced slightly in four bladed applications, but it some cases, if the boat is propped with just the right pitch you may have a gain in top speed. Five bladed propellers offer the ultimate in hole shot and torque, and are popular for ski, wakeboard and water toy pulling duties.
Rake is the angle of the leading edge of the blade relative to the hub of the propeller.
Rake effects the ability of the propeller to lift the bow, with more rake offering more bow lift. The important thing to remember about rake and cup is that they will effect the way a particular engine can swing propellers of the same pitch, but with more or less rake and cup. In other words, of two equally pitched propellers, the one with more rake and cup will put an increased load on the engine as compared to the other. This is important to keep in mind when choosing. You have to attack the problem with some expectations and your baselines in mind.