DM Earring.

As long as you have a decent source of refresh, max mp is highly overrated. I'd just use loq for macro rather than full time.

Assuming the fight lasts long enough to cap your hate out and deal 700+ damage. In meripo, you'd be doing Vorpal. And if you're doing Vorpal, a 2nd sword means an extra hit plus if you roll with a Company/Organics + Joy, you get the benefits of a strong main-hand sword for the initial 4 hits.

I don't meripo on my PLD anymore, but when I did, it was as PLD/NIN with Company + Joy. I didn't need the shield for damage mitigation or spell interruption and I don't believe Sentinel Shield was out at that time, but if it was I couldn't justify the 1% haste for a massive increase to my weapon skills by having both an extra swing and a major bump in base weapon damage. 600dmg Vorpals were hot.

More On Topic:

Suppa is extremely useful for PLD in Meripo and a minor note when in "idle" gear (i.e. gaining TP for Atonement in HNM). Knight's Earring +skill didn't produce super noticeable effects when Ferien tested it way back in the day, probably because you can get so freaking high with other gears (cite: http://www.killingifrit.com/forums/topic/121126-the-killing-ifrit-paladin-faq-22-august-07/) and you'd only be using it for one thing: Uts Recast.

My thoughts? Suppa's useful in merits, but most merit on other jobs these days. Knights is only marginally useful in tank situations when shadows fall and you need to macro a shield set to get those up asap. Bushi is bushi. If I were you, I'd keep the suppa and integrate it into your idle/tp build for Atonement spam.

So does anyone want to sum up?

I find myself, as a career PLD, having to make the Knight v Supp earring choice shortly.

*note no Atonement or Joytoy and no intention of taking a DD to 75.*

I'd say that more important than your DM earring is to get past DM, then finish Sea and post DM crap for your Ethereal. As a PLD that will serve you far better than anything from DM.

In the meantime, I guess I'd say go with Knight, but really look past it for Ethereal because it is simply THAT good.

PLD is a one hander that needs to get to 100 TP ASAP to use atonement.
1handers have lower ACC. More skill = more ACC and ATK, therefore fewer 0 hits. More atonement.
Youe shield skill is only useful when shadows are down/casting.
Suppa is where it's at, yo.

Cheers!

if you have one job that can use suppa always keep that.

Let's assume PLD75 is your only job.

*IF* you ONLY use PLD/WAR, a Knight's earring MIGHT make sense. Truth be told, PLD/WAR is only feasible in Dynamis nowadays.

If you play PLD/NIN, the accuracy boost from Suppanomimi makes this more valuable than the Shield Skill from Knight's earring.

Buckler Earring is almost as good and truth be told, the +2 shield skill difference isn't going to be game-breaking.

There is a bigger benefit to PLDs nowadays using Suppanomimi versus Knight's Earring. Even if you lack atonement, getting a Nyzul disc to 100 is much easier than redoing DM.

Final verdict. Knight's Earring is an outdated piece of gear for 95% of tanks out there.

P.S. L O L @ PLD in merit parties