Which Ayra should I keep?

I would go def+, gives her a better survivability on physical atk units. The +spd can make her as fast as mia(i think thats the mercenary) but Ayra's speed already prevents alot of doubles and the atk- bane hurts her proc atk, although her spd+ is added (if my math is right) you still lose 1-2 more points in damage on proc with the spd+ cause 40% of Ayra's speed is used for calculation yet added with her atk and youll see the difference.

Currently working a neutral Ayra so my math can be wrong....

+def/-res all the way

+DEF, -RES as she needs as much attack power as possible.