Both are a good start for converting flash content to HTML. Both will be evolving. The biggest difference I can see at this moment is that Google Swiffy supports some basic Actionscript 2.0 code and Adobe Wallaby doesn't. Suprising since Adobe owns Flash.
Both aren't the silver bullet for flash on all devices yet. Your flash needs to be simple enough for HTML5 to handle. Definitely a step in the right direction though.
Adobe Wallaby's Release Notes:
http://labs.adobe.com/wik
Google Swiffy's Documentation:
http://www.google.com/dou
What is the difference between Adobe Wallaby and Google Swiffy?
