I wear ANR headsets nearly every day.
I have several copies of the Bose A20 and one pair of the Bose A30. Plus a Zulu 3. Also have a couple of QC headsets. I tried out the Bose Pro Flight 2 for a few flights and gave them away. Of course my application (bizav + GA) isn't pure GA.
I prefer the A20 for GA. Yes, it's more clamping force, but not significantly more, and I can only tell the difference after about 8 hours on the flight deck - and that isn't going to be a factor in piston airplanes. The "science" may disagree but I perceive greater noise reduction with the A20s in my little Twin Comanche and typical single engine pistons (172, Archer, etc.)
The A30 is quite nice on the flight deck of an ultra long-range business jet due primarily to the excellent ANR, great bluetooth audio, less clamping force, and the ability to swap the mic left to right pretty easily. I am very pleased. However, for GA flying I certainly wouldn't make the investment if I already owned a pair of A20s. I'd keep using the A20s and upgrade only when necessary.
After many years of Bose knocking it out of the park, I would say that the original Pro Flight was a true stumble and the Pro Flight 2 was a quick fix which made a reasonable number of people happy, but not me. The A30 is such an incremental upgrade to a powerhouse product that there's no reason to bother with it unless your A20 is dying or you don't own a high quality ANR headset in the first place. It will be interesting to see if Bose's competitors pounce on the miscues over the next couple of years.