From judging their lore and their army strength, I'd have to say the: 1. Hive 2. Vex 3. Cabal 4. Fallen I think the Hive are first because of their close ties to The Darkness, but also their forces in general. Although the Vex are a close second, I don't think the Vex can compete with Wizards and melee Knights. Let's not forget Ogres. The Vex can travel time and whatnot, but they aren't that advanced and let's face it, they haven't killed us or won (yet?). The Cabal have lots of firepower, and out in the open, probably could out slug the other 3, even though they lack snipers like the Vex and Fallen. Goliath tanks and Interceptors would end any of that, though. Plus, from what I understand they use planets as weapons. The Fallen seem to be on the lower rung of danger in my opinion. They have speed from their Pikes, and have stealth, but even with the Archon Priest being a beast, I think they're the weakest army overall. Thoughts and feedback?