PLD: Do you tank with Sword Oath on? I do.

[Kazumac]

As long as you keep hate and as a healer I can continue to dps and keep you up. Otherwise if I have to stop dpsing your sword oath shenanigans have cost the group more dps than was gained.

Though I am actually quite for it as long as you meet the above requirements

[StouterTaru]

If the content was added to the game before the gear you're wearing, by all means use sword oath. If you're pulling multiple groups in the newest content, stick with shield oath.

[DarkLordCthulhu]

I'll go into Sword Oath when tanking coil or ex primals. But I only do it when FoF and Bloodbath are both off CD. I'll just pop a couple defesive CDs (awareness, convalescense, and bulwark) then proceed to wreak havoc. I hit a 1k RoH doing this. I almost ish myself lol

[Akuryu]

Not sure how well it would work in 8 man content when a STR built WAR off-tank is present. Even with defiance off, I'm pretty sure I'd have to hold back to not pull hate off a PLD in sword oath. If anyone is having to hold back that defeats the purpose of doing it. Fine for dungeons though. I rarely use defiance in dungeons myself.

[Parodine]

I encountered a tank would switch like this in a Snowcloak I ran. At first I started face-palming thinking he wouldn't be able to keep hate from all the cures I'd have to throw, but he did wonderfully. Like others have mentioned, Shield Oath for pulls of 4+ and sword oath for the rest. I could have been irresponsible and pulled hate with Holy-spam I guess, but I can do that on some shield oath PLDs, so that's not saying much.

[Fyce]

As an "average" main PLD, I currently have all my right side with STR acc. With a full i120 left side (except for the weapon), this build grants me 7.1k HP in group, without food.
It's more than enough to run any Lv.50 4 players dungeon in the game, plus a few 8-man like HM primals and stuff like Castrum/Prae for the roulette (I haven't test in ST yet as Main Tank with Sword Oath).

I'm now using Sword oath for a lot of content, but I still have some trouble keeping enmity up on a big group (4+ enemies) against BLMs. Since I have to Flash all the way until my MP pool is empty, I don't see a benefit from having Sword Oath up during these pulls (Flash doesn't do any damage... so Sword Oath is basically useless, except for CoS and auto-attaks, but that's really not a big point).

So, now I'm using Sword Oath for bosses if my Healer is okay with that and after a bit of time in Shield Oath if I'm sure that enmity is secured on my end.
For trash, if it's equal or less than a 3 monster pull, I put Sword Oath on. If it's more than that, I'd have to Flash mindlessly to keep up against big AoE damage, so I go with Shield Oath.

... And that's pretty cool to see a 900+ crit coming from Rage of Halone from time to time as a PLD

[Doki]

Sword oath is especially good for bosses with no real hate to worry about like Sastasha HM & Stone Vigil HM. Of course it's always fun to still be in Sword oath from one of those, forget you are, and then try to run a huge pull in a new instance without Shield oath up...

[AkashiXI]

In big pulls in dungeons, I can holy bomb better than you can ST with your sword oath, including CoS. In FCoB, it's viable so long as you're overgearing the content and your healers are ok with it.

[Purrfectstorm]

so tanks can do 50 more dps with autoattacks

Shield Oath also lowers damage dealt by 20% so Sword Oath is raising damage by a lot more than just autoattacks. That being said, big pulls/aoes make dungeons go faster than extra tank dps. That's why I'm full VIT on PLD, pull trash in Shield Oath, and wear Fending Accessories. Even by not needing as many heals our groups get more damage as healer dps > tank dps. On bosses sometimes it's different as I can often still hold hate in Sword Oath.

On WAR I'm full STR but only because I use WAR a lot for PvP, which is a whole different matter.

[Aurora-Pendragon]

I'm only 104 and when I'm being grouped with DPS/WHM using zodiac weapons, I cry a little inside. I'm not at this step of even thinking of using sword oath over shield oath.