Parry...

[Vique]

There are generally several schools of thoughts among tank players (in most MMO's):

1) The faster things die, the less damage you take.
These players will prefer offensive stats over defensive. More damage also means more emnity/threat/aggro. The bigger your threat lead, the more allowance you have to maintain buffs and debuffs (especially true for warriors) and other maintenance duties such as dps-ing adds, stun locking, avoiding crap, etc. without worrying about healer aggro taking over. You can also push phases faster and have to deal with annoying mechanics less ie T6. The less time an encounter takes, the less time u have to make mistakes as well. Offensive stats like strength also have passive mitigation attributes other than damage.

2) Your job is survivability and threat.
This is the official job description of a tank. These players will min max avoidance/mitigation stats and ignore damage completely. It is safe build when potency of healing and dps are variable and inconsistent or if you are unfamiliar with a new content/mechanic. You have to fend your yourself. Encounters usually run a little longer, but you can offset that by surviving better.

3) Avoidance vs mitigation
Essentially comes down to RNG vs predictability. Usually you have to sacrifice one for the other, ie choosing between onion shield and holy/allagan shield. Could be applied to parry I suppose. From experience it depends on the encounter. In my opinion, if you have multiple fast attacking mobs, avoidance is king. But if you are tanking a singular, slow hitting boss, I prefer to take mitigation. You dont normally die from sustained damage. You die because of large, unpredictable spikes. In which case if you have low(er) mitigation, and when the RNG gods are not smiling on you, you are sure to die (in some games).

Of course, there is no prevailing build as no amount of theory-crafting or practical tests can disprove the viability of any of the other builds. To be a good tank, I think one should be aware of all possible alternatives and adjust their build to suit the encounter and his teammates. However in this game, the itemization is poor, and any difference between items of the same ilevel tier usually produce differences that are quite negligible at best. Trading 1% of avoidance for 1% more damage or vice versa is a matter of choice and wont make you a better or worse tank.