Skillspeed is the best substat as long as you cannot fit 9 hits in your Berserk rotation. Around 400 SS depending on your latency is recommended. Accuracy is a good stat to have if you are interested in doing endgame raids + some Ex Primals, and Detemination/Crit are always good.

Parry however, in my humble opinion, is the least useful stat. There is a ongoing discussion right here:

http://forum.square-enix.com/ffxiv/t...rry-yay-or-nay.