At least 80% of the time liberty is superior to tradition. Even in a big FFA, getting those settlers out first snags the resources you want while tradition players can not place cities well. You can build a settler and get a free settler to surround a tradition player early. Their game is essentially over if boxed in. Cities being made earlier means they are making units and money earlier. You have more of everything. Liberty also gets the + 1 production which is big for those small early cities. Let's say you decide to rush a wonder. Liberty winds up with a free city placed and a wonder as well as possibly a free worker working efficiently, tradition winds up with just a wonder, no worker yet and future workers very slow. Tradition is only good with no competition nearby, no unique luxuries or no place to build. Even if you only get 3 - 4 cities up liberty gets them so much earlier that tradition is still placing cities while liberty is on to better things like building an army.