I have one on my RV-6 with 160hp O-320-D1A engine. It's incredibly smooth running. I have the ~ 12 lb Landoll inertia ring on my flywheel too, which probably helps the smoothness even more.
I am running the #5 pitch pin with mine. It'll run right at 2700 rpm at WOT at 8000 density altitude, and can readily exceed 2700 at lower altitudes. I've run the #6 pitch pin last winter in cooler weather, and that helped to keep the RPM from so easily going past 2700 at lower altitudes, but it also reduced takeoff/climb performance and also knocked a couple knots off the top end up high too. The #6 pitch also had a lot more P-factor and needed a whole lotta right rudder on takeoff, so I put it back to #5 and am happy there.