Wedding Cards works well enough, but with the limited number of invitations, bare-bones customization tools, and limited sending options, it is hard to imagine using this as your only wedding announcement or invitation tool. There simply are not enough features and the resulting invitations don't look as polished or as personal as most couples will want.
Wedding Cards has five total cards to choose from, two of which are invitations. Each of them can be customized with your own text, but in most cases that is all you can change. There are no options to add photos, print the cards, or send them to anyone other than online. The cards, themselves, are very generic, too, meaning they don't stand out as being particularly unique or interesting. Once done editing, you can send via Twitter, Facebook, or e-mail. There is no preview option, so you can't be sure how your cards will look with your few customizations, which is another downside of the app.
Wedding Cards is an interesting idea, and with some additional options and features, could be a very good app. As is, however, it is too limited to be used as the only way to let your friends and family know about your upcoming nuptials.