...which appears to be rather unstable, although the crappy plugins I'm using could be to blame perhaps. Seems like no nifty new feature comes without 5 major regressions in the program.
Because it's still in Beta release.
Anything wrong with the way Firefox displays a website is the problem of the person who built that site. Not Firefox.
I was reluctant to upgrade. But I did. It's been just as stable for me as 1.0.7. No problems at all yet.