Before we get too far in this debate, define "best" please. Are we asking which one cools the best, ...which one looks the most authentic, ...which one is the least expensive, --or what??
My vote for which one cools the best and looks the most authentic for a 1931 model would probably be Brassworks 1st, --with a Berg in a close 2nd. My reasoning is the Brassworks has the dimpled-fin core whereas Bergs does not. My experience is the Q/C at Brassworks has greatly improved over the past year or two.