Opera man here. Began trying it intermittently a few years ago, but always fell back to Firefox and it's extensions. But I started to fall in love with Opera after 9.5. Then Opera 10 came along under the banner of being 'the fastest browser on earth' and any lingering doubts disappeared. Great interface, email client, found a few useful things to do with Opera Unite. I've never looked back.
Firefox 4 looks like it took blatant visual cues from Opera 10+. Have used Chrome recently and Opera is definitely at least it's equal. Not sure extensions are yet up to par with those of other browsers and ad blocking on Opera has always been painful compared to other browsers but you have to take the rough with the smooth >.< Only reason I use Firefox now is to view those websites that still can't get their heads round Opera.
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