Memory footprint: If you haven't noticed that Java has an absolutely ginormous memory footprint, you've never used it. Running the test app for Java FX, Java FX Pad, takes 65 megs of RAM on my machine -- and that's one canvas and one textbox. Granted, I think most of that is the runtime, but it launches a javaw.exe runtime for every app. So when I launched another demo off of their website, another 65 megs.
More random memory stats (all IE7 tests utilized a relaunch before loading website):
- IE7 on startup at "iGoogle" home page: 8640k
- javaw.exe running Tesla website demo: 55800k
- IE7: Actual Tesla website in IE7 (Flash, DHTML etc): 29156k
- Silverlight Microsoft.Com demo, after clicking on Products: 30136K
- The real Microsoft.com (DHTML), after clicking on Products: 27740k
- IE7: gmail.com inbox (AJAX, DHTML): 36064k
- IE7: Yahoo Mail Beta inbox (AJAX/DHTML): 40600k
- IE7: Hotmail light (very little Jscript): 18948k
- Windows Mail in Vista and a full inbox: 7424k
So there you have it: Win32 wins again. Actually I think a lot of this, except Gmail and Javaw, can be attributed to imagery. That's probably why there was very little difference between Silverlight and the real Microsoft.com.
Dev tools: For Flash, you've got... Flash. For DHTML/AJAX you've basically got notepad or XEmacs, unless you're using something like GWT. For Java FX we've got netbeans with no UI designer, and for Silverlight we've got Visual Studio Orcas with a designer. I think we know who wins this battle.
Early call: First off, I just don't see the bizarro Flash apps taking over... ever. I've seen good Flash UIs very rarely, it's mostly good for crappy video, annoying advertising and for stupid flash movies. Java FX and Silverlight have a chance, but I think it's going to take a killer website to get it rolling. Microsoft is fortunate to have a built-in audience, and Sun is fortunate to have millions of Java developers who adopt every framework ever made for the language.