There has been a decent bit of chatter on the interwebs lately about the advantages and disadvantages to the rival platforms of Adobe's Flash & Flex versus Microsoft's Silverlight. There are many strong feelings, mostly from coders, on both sides of the debate with valid points supporting their standpoint. I view this level of competition against rival rich-media platforms is a good thing for designers and developers. While I agree that Microsoft has a lot to learn from Adobe from a standpoint of a designer friendly workflow, I also see that Adobe is able to adopt features and best-practices established by Microsoft's vast experience in enterprise development. After all, I think the collective goal of designers and developers is to "make cool shit faster", so who-ever is able to meet this criteria will ultimately be king of the hill.
Here are a few quotes to further illustrate some of the passionate oppositions recently published from both Flash and Silverlight platform advocates:
Flash platform advocate: published by: Jan Ozer
"...Microsoft needs Silverlight to succeed far more than most companies need Silverlight. From a marketing perspective, that’s like pushing the back end of a rope in the hopes that you’ll drive the front end in the target direction. It almost never happens."
"If Microsoft dropped Silverlight tomorrow, most web site owners and 'Netizens' wouldn't even notice, or care if they did."
"Flash caught on because it provided design functionality that HTML couldn't match and solved problems that no other technology could. It succeeded because website designers, developers and owners wanted it, not because Adobe needed it."
Silverlight platform advocate: published by Alex Vanderberg
"The cost of delivering complex business functionality with Silverlight is likely to be significantly less than doing so with Flash/Flex."
"Actionscript 3, as an object oriented language it lacks many features Java or .NET developers will take for granted."
"Flash/Flex developers have years of experience of making good looking applications, but they don’t always write solid maintainable code. This is understandable, given the lack of enterprise Flex projects there have been to this point."
For a more unbiased comparison read the article Flash vs. Silverlight: What Suits Your Needs Best? from Smashing Magazine.