I’ve made a simple, more “hands on” comparison of some ria technologies for who’s interested. Flash, Flex, Actionscript 3 alone, Silverlight using C#, JavaFX, Java and AJAX are covered. You can check the article at http://my.opera.com/facildelembrar/blog/rias-comparison-part-2-simple-programs
The article is update once in a while with more info.

Thanks, I did update the comparison to post latest facts as you see I am updating this regularly.

I am a Microsoft expert programmer since 8 years and believe me, I have experience from ranging from Win32 till Silverlight and all the technologies and languages available in MS.

1. Moonlight is not Silverlight, and its not Microsoft’s.

2. Documentation, till Visual Studio 2003, MSDN used to be very good, but the whole XAML, WPF, WCF and so on and so on, documentation has lost its charm. With so many pages to clearly state in the first line of msdn that “This is premature literature and expected to change etc etc” i dont know exact words, but doesnt that prove premature?
- You can not create default reference value in dependency properties.
- Well Silverlight 1 didnt have dependency properties itself.
- There is too much confusion about how much of .Net features are available in Silverlight 2, because there is no one straight document that explains correctly.

3. Control Library, we are talking about what is included in base SDK by the vendor, not for third party ISVs, even for a control like “Tree” you have to spend money and get from ISV. As we being Microsoft Partner, we know the strategy of Microsoft to promote and give opportunities to its partners by giving limited product out line and allow its partners to make controls and many other solutions without which industry can not run. But now costs have gone prohibitively high to incorporate Microsoft products.

4. Language Features, this point really amazes me as for every different feature, should we use different technologies and different languages? More time is required to code, to maintain, I am a good businessman too, time is money here. This document is less for programmers but more for CEOs and CIOs who have to make their decision based on cost of development, maintanence, availability of programmers, time management is huge issue in today’s IT world as no deadlines are met mostly.

5. Stability, well half of the samples, and half of websites when we visit, it runs some javascripts, detects that you dont have required player so it displays icon to download silverlight 2, you go ahead and download it and come back, once again it displays icon to download siliverlight 2 and so on and so on. Excuse me, you are against world’s 8 year strongest and stable product “Flash” the flash file format has even saved every bit in compressing file sizes and delivering results faster and has ruled world for longer.

6. Component Development, MSDN doesnt have any good samples for Custom Control development, neither in silverlight nor in WPF. There is no control lifecycle discussed anywhere correctly, everything is so disorganized, I belive if you are Microsoft employee, then I am your customer, if you accept and try to work towards it to make better for programmers, it will help you only the most.

You have a long list of things that you are comparing the different technologies on. However, you really need to check your facts before posting statements as fact. I cannot speak to JavaFX or XUL but I can speak to Silverlight.

I will say that there are inacurracies on the Flex side both positive and negative. You should recheck those facts as well.

Open Source – check Moonlight at http://www.mono-project.com/Moonlight. The main player is not open source but there is a fully supported open source implementation being built by Novell under the Mono project.

Availability – I don’t have actual penetration numbers but 0 is obviously wrong. Otherwise, how did 42 million people watch the Olympics through Silverlight streaming (http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9114378)?

Audio and Video – Windows Media Audio and Video 7,8,9 (WMA, WMAPro, WMV/VC-1), as well as MP3 audio – these are all well established industry supported formats that have been around for quite a while. Additionally, Microsoft has announced support for H.264/MPEG AVC and AAC in Silverlight 3. http://www.microsoft.com/silverlight/overview/faq.aspx. These are the formats that are served up by Windows Media Server already and there’s a ton of content out there ready already.

Converters for the Supported Video – Expression Encoder does a great job client or server side. http://www.microsoft.com/expression.

Documentation – define premature. There’s a ton of content not only on MSDN but on http://silverlight.net and countless community sites.

Synax – C#, VB.NET, JS, Ruby, Python or any of the many .NET languages that are out there. Longer list at http://www.dotnetlanguages.net/DNL/Resources.aspx.

Language Features – any supported by any of the long list of languages above.

Code size – depends on what you are doing, what language you use and how good of a programer you are.

Stability – Pre Beta? Really? Silverlight is in Version 2 and has tremendous stablity. The support for exception handling, logging, unit testing and more can help the developer write remarkably stable applications with little effort.

Control library – There’s a lot of controls built in and lots more coming from the open source project – http://codeplex.com/silverlightcontrib.

Component development – quite simple. it’s a different model than you are used to working in as a Flex developer but it’s the same model that millions of .NET developers around the world are already using.

The result – a strong contender that you should look seriously at. It’s the platform you should look at if you are a .NET developer.

I did not correct all of the innacuracies but I tried to speak to the most blatent.

Thanks for update, I am going to update the comparison as soon as time passes by and I get more information, problem with NB 6.5 is, its yet not stable, since JavaFX is still in the form of under development plugin, it lacks continuous professional development environment, you can start something but this is for people who want to create good running apps which are easy to maintain. I belive JavaFX will take little of 6-8 months to get stabilize in NetBeans platform and then it can become good platform to develop on.