The main draw for the many that have been downloading the “Atlas” CTP is to enhance the increasingly more important User Experience – implement the cool stuff behind the buzz phrase “web 2.0” -- quickly and easily. Add slick functionality like grabbing your data from the server without refreshing the whole page, while taking no extra effort for cross-browser support and very little effort to implement an animated GIF that lets the user know the page is refreshing. Also -- there is a lot of emphasis on quick and easy animations in the toolkit, not just data oriented retrieval.
There are downsides however to using the CTP. For example, you can not distribute the Atlas DLL itself; meaning that if you were to build a DNN module you would not be able to re-distribute the DLL with your module. However, you can build and maintain a web site that uses the Atlas DLL. Basically you can’t ship it with your product.
From what I’ve heard the first official release will be sometime near the beginning of 2007 and will ship with the next version of ASP.NET.