I have spent a pretty significant amount of time using webkit 1.4.1 and it is a major improvement over 1.4.0 however it still is in a pretty bad state. I have started working with the upstream folks to get some things resolved however doing anything webkit is painfully slow.
I have run into are crashes, failure to render pages, resource starvation etc. I'd like to suggest we keep a 1.2.x around in addition to 1.4.x for a better browsing experience. 1.4.x will eventually get better but right now it is painful to use as a daily browser.
