Silverlight or Flex? Which one?

[TimHayes]

I have been using Flex for awhile now. Works good. Just wondering if there are any advantages/disadvantages of using Flex vs Silverlight? Is there a reason why you would choose one over the other? is there a Flex vs Silverlight Functionality Matrix?

[MikeHargreaves]

Since HTML5 was mentioned in this forum, I'll ask my question here.  We have an HTML5 viewer that works quite well for viewing:

http://agsmaps.ci.santa-rosa.ca.us/Html5Viewer/Index.html?viewer=PublicHtml5

But when I set it up for editing, I'm running into periodic lock errors - any ideas why this might be happening?  I'm wondering if I haven't set up the GDB correctly...