Some known issues remain after the 18.0.1 patch, but version 19 will clear up several of them.
The most important fix applies to a HTTP Proxy Transactions problem, which could hinder or stop browsing in a worst-case scenario. Two other big fixes are only for Firefox on Apple systems. The Unity player plugin was crashing on Mac OS X, and the browser was having trouble with certain high-resolution Apple screens.
Plenty of known issues remain, including a bug that makes Gmail’s main screen scroll slowly, as well as a glitch that can tank Microsoft System Restore, but all-in-all, this update is worthwhile.