Part of my preference for the PA-06 80 over my PA-07 74 or the PA-07 80 I think has to do with the 74 and the newer model 80 being more dedicated for wave sailing. I don't find them as smooth of a ride in really harsh chop compared to my older 80. I also sail in a place where the wind isn't always steady so the 80 carries me better on small sails if the wind drops a bit. I also like the PA80 in really high winds where I'll sail a bit backed off on the power in the gusts. As I mentioned on the other thread I'm such a fan of the PA80-06 that I have two of them. I haven't sailed the K80 a lot because I prefer the Q76, but to me it feels distinctly smaller than the PA80s and a bit smoother than the newer versions of the PAs.
Regarding the Quad and high winds in the Gorge this summer, I found I was carrying 5.0 when most people my size were on 4.5s and sometimes smaller and if the wind dropped I could stay out without changing up.