Actually, if you have been going with nightly builds (as i have, each morning fresh new build downloaded and waitng for me
there is not much new to drool over. If you stayed with 0.9.6 as your last build then upgrade is well worth even if only because of working SSL support (finally) which made it in shortly after 0.9.6 was released. Notably new thing (which is documented in Release Notes as well) is ability to configure some Javascript options separately. You also get dynamic theme switching (made it into nightly builds early this week) - you don't need to restart Mozilla for theme change to take effect.
One thing which keeps creeping in into build after build is crashing the whole damn browser when right-clickin on image map link area. 100% sure crash on my two comps (w32). At least K-M doesn't do that
Oh and you don't get that sexy 3D x-button on tab window with 0.9.7 release that you get with latest build :-P