>>536505469
Depends on the supports you're using and her ammo rolls. With Crown, resilience is usually better as long as you time your reload correctly.
But if you you also use Siren as a B1 and you have a fuckload of ammo on RHH (1100+), Bastion may be better as she can lay down fire for a long time before reloading.
With Crown and MMast, resilience is a no brainer, as you have instant reloads.
Without any of the good usual supports (why tho?), Bastion is a better pick unless extremely low ammo count.