When you compare ShopperPress next to Yak or WP e-Commerce it doesn’t take you long to figure out the authors of this Plugin are more bark then they are bite. The themes are less then appealing and the features are lacking many fundamental e-Commerce features that are expected in this day and age (for example just compare the shipping options available in each of these Plugins).
One must compliment the authors on their marketing talk. Unfortunately their walk don’t talk. Our recommendation, at least for the foreseeable future is to stick with the Plugins that pack the most punch and takes the biggest bite and for your online business we reccomend you use the WP e-Commerce Plugin or the Yak Plugin.