Flex vs Silverlight

The debate between Flex & Silverlight is getting pretty hot on the web, Silverlight is an entirely new platform for any developer to write to, but it is backed by one of the most experienced and resourceful software companies in the world. Flash, the root of flex has been around for a long time and already has great market penetration of the flash player. I will highlight below some of the main points in the debate that stand out as relevant to me.

Pros for Silverlight:

• Brand New, Doesn't need to support legacy code like the flash player (more lightweight browser plugin)
• Brand New, Any example, book, tutorial, or implementation is written in the current language
• Brand New, Microsoft will help in the marketing hype of silverlight applications
• Microsoft Backed, Will continue to be supported as long as Microsoft is around (forever in software time)
• Built-in data connectivity and relationship to a powerful web language (ASP.NET)

Cons for Silverlight

• Still in Beta, not much as far as examples, resources, books, experts, communities
• More to download/purchase to start developing (SDK, Visual Studio, Expression Studio)
• Almost no user has the plugin already installed or would recognize it (The Microsoft name will help here though)
• Personally I have no experience with the language (Not silverlight's fault :) )
• No publicized plans to do an apollo like implementation (Adobe's desktop version of flash)
• Not an open-source mentality among developers
  

Pros for Flex

• Flash Player is already all over the web
• Easy to use flash components in flex apps
• Great language specific IDE (Flex Builder 2)
• Easy to understand language
• Huge community of impressive open-source tutorials, examples, and apps
• Responsive community of experts
• Adobe is a huge player in the web-based graphics arena
• Apollo base that will allow a flash web app to run like a client side app
  

Cons for Flex

• No built-in server side language support
• Adobe is not as recognized for business applications when compared to Microsoft
• It is a brand new language, not a lot of precedence for business apps running on the flash player

As a note these are criteria that I thought were important to for myself, my work, and my clients and after considering these tradeoffs I went with Flex. I have been very happy with but still plan to tinker with silverlight once it becomes a bit more established.