The latest version (1.0) is still just a preview release. You can check for yourselves by clicking on help and then "about mozilla firefox". There you will see that version 1.0 is a "preview release" and not a final version.
I agree, it's a nice change from IE
but unfortunately, there are still some sites that either don't work at all with anything but IE
(Yahoo's LaunchCAST radio) or only partially work with other browsers than IE
. If Mozilla wants to be considered a true alternative, their marketing people need to get on the stick.