Re: [2] Since Opera got extensions, it doesn't make less sense to me (as a browser "power user") than Chrome or Safari. Fact remains though, Firefox extensions

Re: [2] Since Opera got extensions, it doesn't make less sense to me (as a browser "power user") than Chrome or Safari. Fact remains though, Firefox extensions can do a lot more low level changes to the browser than the Chrome/Opera extensions. The level of configurability has its pros, and cons (stability). Tree Style Tab extension ( https://addons.mozilla.org/en-US/firefox/addon/5890/ https://addons.mozilla.org/en-US/firefox/addon/5890/ ) is one extension I don't want/can't to be without. It would not be possible to achieve the Tree Style tab user experience in Opera/Chrome. At least not today, most likely never.