I love fresh ivy in bouquets, corsage and boutonniere work.
I generally soak ivy in a tepid water bath for about 20 minutes before use and then spray with a leaf polish such as Leafshine. This isn't a "have to" . . . but it does seal the leaves and make them last longer. I sell smaller cans that are perfect for single wedding use.
You can use silk ivy accents - just be sure to look for clean cut edges and small leaves. It's doubtful if your guest will even realize that the ivy isn't fresh.
I like the wired ivy, but it is a little more expensive and the cost is comparable to a fresh bunch of trailing ivy. It's really just a matter of personal preference.