Well, it is replacing SiteAssist Pro as a product. There are added features, but you can have both of them installed at the same time without running into issues.
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.