Do you use umbrellas for for group photos during weddings?

Do you use umbrellas for for group photos during weddings? Do you have a before (without the umbrella setup) and after (with umbrella) shot so we can see the difference?

I run on the cheaper side of things for the weddings that I've done. I use a pair of Nikon SB-600's each with the Gary Fong Lightshpere on light stands. I've been satisfied with the results although I have been considering adding one more setup that would be more centered. No matter what, every church that I've shot in has needed extra lighting.