SMN and materia

I apologize if this has been asked before, but I'm trying to figure out which materia and stats to prioritize.
I'm in mostly 320 gear with some 330. I'm looking at the accessories for the 330 gear and I see crit/DT/DH being replaced with spell speed making me hesitate on getting those pieces.

However, regarding everything else, I'd like some advice on a few things:
1) What materia should I prioritize.
2) Is there a cap - both hard or soft where exceeding X won't be beneficial.

Currently my Crit is about 1050, DT 984, DH is about 1500. (I can confirm this when I''m home though).

Any help would be appreciated.