Should I use an ebook aggregator to publish my ebook or publish myself?

Authors who are choosing to self-publish their ebook now find themselves faced with a number of questions regarding not only how to get their book into the correct formats but also what to do with those files once they have them. Most frequently, they want to know how they can get their ebook to Amazon (for the Kindle), Barnes & Noble (for the Nook), and Apple (for the iPad). In addition, there’s the Google eBookstore and Sony, among others.