The way I see it Pld is the better tank in most situations, but could revolve around a few things.
Is the other tank a Pld if so the going war might be better, assuming the Pld can fit there needed requirements.

Since I play both and enjoy both kinda falls into "I prefer to MT" but one might be better then the other at certain things. The bar kinda leans in Pld's favor for this -pre patch-.

Consistent dmg or need consistent migration? Pld
Know the fight? Not much consistent dmg but dmg is more timed/spiked? War
Need silence? Pld
Need Stun? Pld
Need a good OT? War(since debuffs)

Here's my list:
T1: Pld(since I silence, if 3+ stacks)
T2: Pld(since I silence)
T4: Pld(since i MT)
T5: War(Better MT, pld is needed to stun dreads unless your running like mnk+drg or dps is really high, RoH debuff helps tho) If i got Pld on this it's straight Str accessory/myth wait over allagn etc.

hm's:
Ifrit: War
Garuda: Pld
Titan: War or Pld
Ultima: War

EX:
Garuda: War
Titan: adds?War/ MT:Pld
Ifrit: War

Relic quest:
Chim: War
Hydra: Pld

4man dungeons: Pld

So it's boils down to what is more effective to play, it that case Pld and War. War is more fun to play but having healer jobs/2nd char is healer only. I'd vote Pld but a good War is uh good>_>. Hate is not really a issue for either unless your fighting for hate.

So Id say both or just pick the one you prefer to play.