In your opinion, which faction is the strongest in Heroes 5? Let's discuss the advantages and disadvantages of each faction.

P.S. Of course, against Necropolis, Inferno, and partially Academy, the Phoenix is useless, but it's very difficult for the others to stop it. And a really strong one can be summoned, and what's even more important, obtained in a guild: Mages, Necromancers, Dungeon, Sylvan.