Whenever I read about new dynamic data controls, I always wonder if they're finally customizable enough not to end up being a pain as your app grows. The asp.net 3.5 model looks very promising! The presenter shows that you can code together some very useful customizations with ajax widgets and dlinq dynamic data support (new attributes and partial methods) in a very short order to transform the default "giant dynamic grid" UI into something non-nightmarish for ordinary users.

Even still, with all of the frameworks available today, you are right to wonder just how much you really have to do to move from the default generic view to your final, ideal custom view vs. just deliberately designing with a narrow focus using the regular tools, and how maintainable and performant the dynamic core will be once it's layered with all of your custom templates.