The Swamp faction is strong in the early game, but it's not that cheap in terms of resources (you need a huge amount of wood for just the upgrades).
But wood is a huge advantage!... I have a very positive attitude towards this faction, and if I have to play on a map with a lot of "sea areas," I almost always choose the Swamp, put a moderately armed hero in a boat, and after a week, I have a whole warehouse of wood... I think many people do the same. :smile30: