Rehearsal Dinner Dress - the Sheath Showdown

Rehearsal dinner planning is WAY down the road, but in the interest of being financially savvy, I'd like to wear something already in my closet. Here's a couple of options that could be appropriate.

In the first corner, contender A:

I recently got this gorgeous Nicole Miller gold brocade dress for 75% off retail-- normally I can't find anything left in my size, so I jumped on the opportunity!

In the opposite corner, contender B:

I've had this ivory silk J.Crew sheath for a couple years now; originally I got it because the online price was something like $20 and I knew I'd wear it somewhere. Sorry for the peekaboo hanging strap! Those things always manage to sneak out. This is the best pic I have of the detail; will have to get it out of the closet and take some better ones.

What do you think? Gold, ivory, or keep looking?