I took some time on this holiday break to start experimenting with Silverlight and Flex, neither of which I have any experience with. While I was toying around with them I started thinking about the dizzying number of the RIA framework options.
With Silverlight I really liked developing in Visual Studio, it was intuitive and fast. I also liked that fact that I could use XAML to markup the layout, then back it up with C# for the event handling.
Flex looks good too. I especially like the fact that you can mark up your presentation in an XML format (MXML), similar to XAML. I am not a fan of ActionScript though, but I will have to see how east the IDE makes editing the code when I get that far.
Then there is GWT. Well, I liked that so much that I wrote a book about it. I like the fact that I can used my editor of choice (Eclipse), code in Java, and it is open and free.
I once used Ext-JS on a large project, and although it looked great it was extremely painful. When I got done the code was completely unmaintainable.
I have also dealt with Scriptaculous, Prototype, DWR, and other tools over the years, but for smaller projects that probably can't be considered RIAs.
Then there is Wicket, Echo2, blah, blah, blah... so many to choose from!
So which is best? I am partial to GWT, mostly because I know it the best, and it is free and has a great community. On the other hand, I could get used to Silverlight (although the cost can be prohibitive).
If you have an opinion I would like to hear it.