2 VIT is *not* equal to 1 DEF. Yes, you get a bonus of 1 DEF for every 2 VIT you have, but VIT does far more than that.
Both VIT and DEF lower damage but they do it in different ways. VIT has a more direct impact on the damage calculation and is essentially subtracted from the attacker's STR (it's a bit more complicated but that's the basic idea). DEF on the other hand acts as a modifier on the attacker's ATK and is used to generate a random number that is then multiplied by the number calculated with STR and VIT.
In addition VIT makes cures more potent. In fact 1 VIT has more impact on cure than 1 Healing Magic Skill.
These points combined with the fact that DEF is comparably easy to get; I highly recommend getting these rings. The ring slots are an easy place to stack VIT early on.
Edit: No, I'm not mixing up MND and VIT. Example: 73 VIT, Cure=32 Cure IV=380. 73+35 VIT Cure=33(+3.124%) Cure IV=387(+1.842%)
A must for PLD's lvl 14-36, and cheap too ^.^. Go for the +1 if you have the extra gil, otherwise just stick to these, there is such a thing as overkill lol.
As a note to some of the LOLPLD's out there inhabiting the Dunes and other places, just because you are elvaan or galka, does not mean you do not need VIT gear, more is always better, and DEX rings will do very little for you, as you are using a one handed weapon (therefore less acc bonus) and your critical hits do relatively little as well. with these rings, your high and low damage rates will decrease, and so bringing less burden on the WHM, not letting the mob dispel as much hate each hit, and making it easier to keep hate.
