Its always better to stack -Magic Damage Taken until you reach the 50% cap before stacking MDB, so if you are in a Signet area Resentment Cape will normally be better.
Why did people rate Bautier down when he's 100% correct?
The only thing he didn't mention is that you only need around -25% MDT depending on how many merits your WHM put into Shellra V (which should be maxed anyways).
hmm PLD can never have too much MP and 65+ you start to fight imps who like to throw Magic so good for PLD imo its also cheap on my server too and you also have to remember if you are a Galka PLD Chasing for MP is something that always hinders you