I have not used Powerstore itself, although I have used both eCart4 and eCart5 to built quite a few shopping carts.
If you are looking for a quick eCommerce sollution, Powerstore gives you the whole thing, including the admin very quickly.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.