My favorite part of Feud tends to be the extracurriculars and the host/contestants chewing up the scenery, so I tend to prefer the formats that left the most time to kill.
Favorite's the original Dawson format from 1976-79. First to 200, Single x2, Double thereafter. For a five player team it also meant you could bring along someone slower who you still want on the team but don't want having to play a high-leverage face off. It also meant tons of time to kill, which usually led to a lot of fun - there's a reason a lot of the show's most interesting moments come from the first three years.
Second: Bert's Family Feud, Australia (2006-07). Single, Single, Double, then faceoff Triple, first to 200 wins. Mostly the same as the above, and really appreciated it as an improvement on what the US syndicated version tried to do its first few years (making R3 double, 200 instead of 300)
Least Two: The 400 point format by a country mile, with the Dawson '94 format coming in second. Dawson '94 was everything bad about the Combs era Bullseye format, but worse (Fewer 'Bankroll' questions causing odd bank amounts, a starting bank of $2500 in the front round, Entirely too much game for a slowing Richard).