As you can see the latest stable version of Moonlight is 1.0.1, which is roughly equivalent to the Silverlight 1 release. AFAIK the latest version of Sliverlight is version 3. I have seen very little content that actually works with Moonlight, it seems most everyone is using at least Silverlight 2 (including Channel 9).
Although in my opinion the Mono team consist of some of the best .NET programmers around, it's very difficult to keep up with the huge developer teams at Microsoft. Mono's full time development team (which Moonlight is a subset of) is actually smaller then the entire .NET Compact Framework team.
Of course this doesn't address the issue that Microsoft has a vested interest in ensuring that Silverlight only works on Windows, should Silverlight ever actually take off as a disruptive technology on the Internet. Adobe, who is not primarly a platform/OS vendor has no such conflict of interest.