I personally dislike the built in bittorrent support (which I know you can disable) I also miss my favourite add-ons such as ad-block plus and no-script I think if opera integrated an add-on like structure like Firefox I would switch in an instant as load times are much better
Each to his own I suppose.
I can't really comment on the bit torrent client - I have never used it. As for add-ons then my view is that if your browser needs add-ons then it isn't complete, Opera is, it has its own adblocker so you don't need adblock plus. As for no-script I tried that on Firefox and I found it to be such a nuisance that I removed it.
Apart from speed, the major advantage of Opera to me is the way it handles privacy matters like Cookies. The Firefox model where you have to type the address of every 'Exception' to your global rules into the 'Preferences' dialog is a major pain. In Opera you just right click the page in question and select 'Edit Site Preferences' and you can set virtually anything you like. This is a far more elegant solution. That alone make it preferable for me.
Don't get me wrong, I still use FF and it is still a good browser I just think Opera is slightly better designed. Having two browsers is a bit like having a backup of important files, if Opera fails to do anything that I want it to (and it used to quite often, but it doesn't any more which is why I made the initial post) then chances are that FF will do the job for me or vice versa.
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