Let's identify the strengths of each tanking class. How do they perform in the following areas:

-Mitigation (armour, pure reduction, etc?)
-Avoidance (dodge, parry, etc)
-HP (um... Yeah....)
-Life Saving cooldowns (shield wall, etc)
-Magic Damage
-Threat?

Given these factors, what is each tank good at? I would especially appreciate input from beta testers.

Blizzard has already stated that they want all tanks to be viable, and picking apart each class just so we can come to this same conclusion isn't necessary, especially if it's (most likely) going to derail into a shit-flinging contest.