It seems to me that the Mozilla project’s stock has been falling since Apple announced Safari and people realized it was based on KDE’s KHTML and KJS rather than Gecko. It’s important to remember that there are more reasons that Apple might have chosen to use KHTML than the most obvious Gecko bad/KHTML good dichotomy that seems to be rapidly ossifying as the conventional wisdom. KHTML is an HTML rendering library written to work with Qt. It is, by its very nature, infinitely simpler than Mozilla, which just by virtue of being cross-platform takes on a lot of added complexity.
I haven’t looked at the source code for KHTML or Gecko, and even if I did, I wouldn’t be able to judge which would suit Apple’s needs better. It’s important to remember that people start a project (like Safari) with specific requirements. The judgement that’s made when pulling in outside components is which of them best fulfills those requirements, not which of them is better on some absolute scale. Emacs is a great editor, but you wouldn’t choose it if you needed to add a text editing component to a Windows application.
And the thing is, we still don’t know whether Apple made the right choice in picking KHTML to power Safari. Is Apple going to commit to the level of standards adherence that Mozilla has worked toward? If not, does that set us behind as Web developers? We’re finally getting to a point where you really can write pages that validate to an actual spec and have them work for just about everybody. I really hope Apple doesn’t move us away from that.