In the siege defense of Blood the other night it was the first time I had put on a shield and made it a part of my to go bag...

Those of you that use them more often, should I be trying to get higher level shields as part of my go bag?

Best you can get and equip

Are they strength based? So the idea is to pull it out and parry when in a bind, and low on mana?

shield and parry is the most OP skill in the game if your opponent doesn't use disable. Not sure what role you run, but as a primalist it is the only way you will live through fights.