Ok so I believe I now have all the 346 Tanking belts and have taken a good long look at the Justice Points belt as well. For all I can see, none of the currently available 346 Tanking belts can match the Belt of the Ferocious Wolf which is a faction Reward bought after reaching exalted status with the Guardians of Mount Hyjal.
So, first off, I know this is intended to be a DPS belt. That said, Ret's Primary Stats across the board in Cata are identical with Prot. The only off thing here then is obviously the Secondary Stats. The Mastery here, however, is rated our best Mitigation stat to stack until we are no-white defense capped (according to EJ). So that means that the Primary stats are far and above, and the secondary stat has one of our best options as well as the ability to reforge Crit into Parry/Dodge/Hit/Exp depending on our needs.
So basically - the question stands as has anyone figured out a better option for Heroics/JP level belts for Tanking?