I'd say Strength is going to win out.
1 STR = 2 AP
2 STR = 1 SBV
I also had alot of gear w/ SBV coming into Wraith, and with re-itemization we are seeing STR become a main stat on all the new gear we are finding and even pre-Wraith gear. I know SBV contributes alot to mitigating the amount of damage taken, so for things like AOE grinding it can be especially benifical. But personally I think in the end going for STR is a better choice. More STR = more AP which is more DPS.