I got curious about the math so I did some calculations of the vectors in a climb.  Assuming the wing angle of attack during climb is 3 degrees higher than at cruise,  The "down" blade (right sided) has a 0.5 degree higher angle of attack than the left side blade.  Further, the right blade sees a 3% higher apparent wind.  Both effects will make the right blade produce more thrust.  So it is probably significant.  The total thrust is something less than 700 pounds at that (130 mph) speed, so what would the thrust difference be?  At the highest I would guess the difference is less than 10% and that calculates to a torque of 280 ft-lb trying to turn the airplane to the left.  But to some extent the prop "makes" its own wind and that reduces the effects.  But there is also the sprial slipstream that is acting on the tail and turning the plane left.  Also, the engine torque itself is trying to roll the plane left (noticeable if you have a P-51).  But the question was, is there a difference between 2 and 3-blade propellers?  I say the difference is very, very minor.  If the 3-blade has a smaller diameter, the effects of asymmetrical thrust is a tiny bit less than with a 2-blade.  Other things being equal (they never are), the 3-blade will produce more static thrust because it has more blade area, but the smaller diameter is working against it - a rule of thumb is that the static thrust is proportional to the square of the diameter.  But the greater blade area of the 3-blade has necessarily higher drag, which makes itself felt at cruise.  And then if the diameter (of the 2-blade) is such that the tips go transonic, the drag can go up a lot.  Thousands of detail compromises have to be made.  Each blade "flies" in the wake of the previous blade, so the closer it is the poorer the effiicency.  The thrust, and consequently the amplitude of the noise pulse of each blade is less with more blades, but the frequency is higher.  So you pays your money and you takes your choice.  To me, a lightweight, slippery plane tends to favor the 2-blade.  But most everyone puts a 3-blade prop on them.

Hopefully reading this dissertation didn't cost you more than it was worth :-)