Well from what I've heard, that Mirroring shield is a pretty good defense item, and pretty important for battle. I personally haven't used one, but I've seen mentions from some battlers that it's quite useful.

Of course perhaps check the battle forum for more help. ^^; sorry this most likely wasn't any help.

Well, they've been in the cash shop before, so they'll always come back if you can'y get one now.

I will be keeping my chancellors shield when the war is over, it looks good, and it reflects icons back making it worthwhile, I may get the mirroring shield as well