I had the same 'I-wanna'
I also wanted to get the 3-blade Hartzell. They look terrific!
At SnF I talked to Hatzell engineer and Sean Tucker and a few other persons.
Caveat - This is accessing my cranial data-bank as best I can.
Harzell engineer said that the engine+propeller operate as a system and that is how it should be evaluated. The lighter 3-blade composite propeller doesn't absorb the vibration and harmonics created in the engine as well as the heavier metal prop does, which has been how the system has been designed for quite a few years prior to the 3-blade composite entering the field. Hatzell testing found that rotating engine components (crank shaft, cam shaft, and the gearing in the back-side accessory case suffered fatigue and showed signs of developing failure.
Sean Tucker asked me, when I posed the question of which propeller should I consider, "Do you plan to do regular competition aerobatics?" He said that if I wanted to regularly execute full power straight up maneuvers I should go for the 3-blade composite, that is what it did best. BTW, I have heard more than one report that he disassembles his show plane completely every year (engine and airframe) to do a thorough inspection. Plus the 3-blade composite was just under double the price of the metal 2-blade, plus the spinner was $1,400 - 4 years ago. I am very pleased with the 2-blade metal, 74" diam, constant-speed, HC-C2YR-1BFP/F7497 PROP.