1) Castle, Stronghold (the most stable and evenly balanced factions)
2) Fortress (fast and powerful, but I don't really enjoy the swamp gameplay)
3) Necropolis, Dungeon (roughly equal. Dungeon is more fun at the beginning, Necropolis later on. Unstable factions)
4) Inferno (the only problem is the low initial attack power, but otherwise it's a very interesting faction)
5) Tower, Conflux (I'm not very good at playing with them)
6) Rampart (a strong faction, but I don't like playing with it and I don't let my opponents play with it either)