Struggling between these two for wedding guest dress!

Both dresses are appropriate for the occasion (bride confirmed) and climate. Both are also comfortable and well made. My big gripe is that one of them is silk and was $700 and the other was $30 - can you even tell which is which haha. I really do love both and not sure which one to wear. What do you think? hair is probably accurate and both are the same length.

edit: This isn’t a ‘which to keep’ - i have both and have had both for a while.