Browser works as expected, no crashes so far (and no problems with flash, using v10)
When testing the language pack, thus starting firefox from commandline, I noticed this:
bad string content
(firefox-bin:12486): Gtk-WARNING **: Icon cache '/usr/share/icons/hicolor/icon-theme.cache' is invalid
Not sure whether this is because of the package or just my installation. Will test it a bit further when I have time to do so.
EDIT again: error also pops up after downgrading to 3.0.3, so the problem is probably to be found somewhere inside my box