I love the idea behind program. You create an account, paste in all your purchase links, and the script is generated for a purchase button with dropdown options for format (epub, kindle, print, etc) and store (amazon, barnes&noble, smashwords, etc). It recognizes where the visitor is located and sends them to the store in the correct geographic location when they click (this alone makes it an awesome tool for authors). The program is funded via affiliate links, which seems fair given all the time the creator put into the program.
Unfortunately, the plugin did not work for me. As another reviewer said, it did mess up my theme, but corrected itself when uninstalled. With certain themes it does appear that it will work without the plugin installed (just cut and paste the embed code); however, I am having some trouble getting this to work with my theme. I'm still keeping my fingers crossed that the bugs can get worked out and I can get it running on my sites because it really is a great concept and will be a great asset to authors.