I think that there can be big differences in the way that boats with full keels actually sail.
Very true. My keel was a "go faster" improvement at one time.
I'm with Bob on PHRF #'s too, and looked at mine before I considered the boat. 156 sounded good for a boat design from this era.
But when I sail next to my friend Georges J35, he points at least 10 degrees higher, while he's going,... faster.
I think people put too much emphasis on specific design details when it relates to a boats speed. If I put Georges 7' foil fin on my 1961 hull, things wouldn't change dramatically. It's the sum of all the other design differences, hull, rig, sails, etc etc that make his J35 70 seconds a mile faster.
I love Georges J35, I just prefer the feel and experience I get sailing an older style boat. I'm not sure new boat design has improved that aspect but that's just my taste.
My favorite sailing is in light air with boat speeds under 5 knots.
Racing has spoiled too many good sails for me.