I tried the sample controls demo in IE7 but it didn’t work quite right. For example, the Picker pane opened but would not close. Tried again in Firefox 3.0 and everything was fine.
I’ve got no idea what the problem is with IE7; it is probably because of weak standards support in IE. However, it illustrates the advantages of a plug-in like Flash, Silverlight or Java. With these platforms, the application is largely insulated from differences between browsers.
The snag with the proprietary plug-in approach is that the vendor may not support every platform equally. Microsoft is entrusting the bulk of Silverlight Linux support to a third party. There are also issues of control. Apple most likely does not want any runtimes on iPhone because they open up a route to application deployment that bypasses its App Store and 30% revenue share. Google seems wary of Flash; RoughlyDrafted says that is because of the risk of content being turned into “opaque binaries” that are beyond the reach of its contextual advertising analysis, but it may just be reluctance to cede such an important part of its platform to a third party.
I would be interested in comments from developers about what RIA platform you are choosing, and why.