What tier are Path of War classes?

I know what class tiers are, and I know what tier most Pathfinder classes are. However, I have recently discovered Path of War, an alternative rule system published by Dreamscarred Press. It introduces many new classes to the game, and I don’t think I know the system well enough to judge every one of them without witnessing them in play, which I haven’t done yet.

On the other hand, I want to know which of those classes are actually good and which are not.

So, which tiers do Path of War classes belong to?