1. The difference is, that we put the main Deals features in to a extensible plugin available here. Most of the additional functions from the other plugin are available in extensions. So there will only be one main version from now and this is the one you can download here.
Previous customers get all the extension from the features which have been included in the previous version for free and can download them within their wpsocial.com account page.
2.) We also created a deals extension for WooCommerce which we will release within a week. It contains the same features as the main plugin here plus some extra features. We will announce it as soon as it's ready.