One particular complaint that receive most of my attention is this:
Firefox does not use Cocoa controls. However when they tried to copy the OS X buttons they must apparantly made a few mistakes, because the buttons does not look anything like the OS X buttons. And as soon as a few effects are added it just gets worse and worse.
Standard Safari button
Standard Firefox button – notice the difference on the edge
OMG! Did you see that? I saw at least one, two, no, three pixel standing out on that firefox button! that’s friggin ugly!
Honestly, who cares? the browser is doing its job fairly well, several magnitude better than Firefox 2 and I currently don’t have any complain against it.
One comment that I wholeheartedly agree:
Anyway… I settled on this for my current Firefox 3 theme. Very nice and simple!