Agreed, for Firefox vs Chrome the insane memory leaks are the main disadvantage and the addons are the main advantage.
I'm still using Firefox, but on my (slightly older) laptop I'm rather close to migrating to Chrome out of necesity. One gig of ram simply isn't enough anymore, and Firefox needs to be manually garbage collected (restarted and the session restored) every five hours or so. My workstation has 4 gigs of memory and needs a GC every two or three days, so it's still usable.
So as a slight hint to Mozilla: you don't need to collect any user data, you need to fix the damned memory leaks!