If full keels were as a rule, faster, every race boat on the planet would sport them. They aren't, but that's not really germane to the argument... which was what?
Personally, I'd have a B-40 because it sails well enough for my mission and has the prettiest shear spring ever put to paper. Wide side decks are also a huge plus for my preferences. And did I say it's just a beautiful boat with half the interior volume of anything made in the past 2-3 decades?