I want a practical browser that does what I need it to. Yet with each new release of Firefox we tend to see further useful functionality stripped away, additional config panel options removed, and the UI dumbed down in one way or another. So whenever an update happens, it's off to searching for add-ons to basically undo whatever unhelpful changes the developers have just made.
Add-ons and customization should be there to enhance and already good piece of software. They shouldn't be there as band-aid that's applied to fix the numerous mistakes and bad decisions of the software's developers.
I find that with every release of Firefox, I need less and less addons. Better dev tools? Okay, goodbye Firebug. Download popover instead of a different window? Goodbye DownloadStatusBar. Australis? Goodbye Firefox-button mover and FXChrome (I use Tree Style Tabs, but FXChrome make everything else look prettier anyway).
In KDE I can hide the FF window decorations, and it then uses no more real estate than Chrome, while still offering a better native UI. I'm just crossing my fingers that any UI changes in FF don't negatively impact us Linux users or drift too far away from native widgets.
I get frustrated because all the people who complain about the new Ausrtalis UI seem to want to drag FF back to the oldschool Netscape/IE6-looking thing. I think FF's UI is in a perfect place in the current version - clean, crisp, and compact. My only complaint about current FF is the redundant "bookmark-star" button in the Address bar that I'm constantly accidentally clicking.