Never had any problems with Firefox updates. Switched to Chrome because Firefox leaked memory like crazy and because unusable after less than a week of work. I use browser quite intensively and keep tens of tabs open at all time. Firefox seems to be unable to deal with it. I suffered for years but once Chrome got decent extensions that was it.
How long has it been since you tried Firefox? Its memory consumption has improved a lot recently. And FF15 will prevent the vast majority of add-on leaks (which was the biggest remaining problem).
