I have a 50 WAR with the relic weapon.
I have a 50 PLD with the grand company weapon.
After playing both.. id take a PLD anyday over a WAR.
Now, im not saying WAR can't tank, its just easier with a PLD for the healers/group. I can tank with both and have no issues IF the rest of the group goes perfect.... PLD just takes damage much better.
The primals aren't that hard as a tank... after playing both i honestly dont see why people say WAR is harder to tank with.. its only harder as they take more dmg..
Ive yet to run into a fight that takes any effort playing either tank. It comes down to your healers and DD's not standing in shit..... And PLD makes it easier on the healers.