I may have a bias Opinion when it comes to this Topic. An that Comes from my experiences, weather flying behind certain props, or all the Dynamic balances I have performed.
The 3 Blade Hartzell is just rougher than a 2 blade or a C424 McCauley 3 way prop. Why? Hell I don’t know. Could be airframe related, or just the fact that a 4 Cylinder Non-Counterweight Engine doesn’t like them. But with that being said I can balance one to where is a smooth at a Turbo-Prop on the ground, But when it’s in the air is when I sometimes get some Lack Luster Pireps.
I spent many hours flying a 67F for my previous employer with a 2 way Hartzell. It was smooth as you could ever ask for. Then one day he sold the prop off the plane, an I had to build a 3 blade from Serviceable parts we had. Once it was on the plane it was balanced just like the 2 way was.
It just wasn’t as happy in the air, an it was a tad slower. But it made up for that in the climb.
Talking about that same Propeller, I Ferried a J Model with that Propeller an it was Turbine Smooth.
Long Story Short, It’s happier on some planes than others.