Eh, it's harder to cap PDT than MDT for most jobs (esp. melee) to be honest as you only need 23 or 26% MDT (depending on shell V/Shellra V) which can pretty much be got with coral+1 or merman's stuff for a lot of jobs, whereas you're aiming for the full 50% wih PDT sets and wont want to be swapping in terra's staff if you're engaged.
Incredible piece for any job that gets this, even if it's just to macro in when you take hate. Obviously it's best suited for PLD, NIN, RDM, WAR, BLM for tanking / soloing. I'm sure other jobs can justify it's use. Just a great piece all around to add to your PDT set.