The Opera browser sucks.
It's supposed to be the fastest browser (that's what some independent benchmarks say). It's supposed to have the best support for latest standard HTML and CSS. Still - a lot of sites, which are supposed to be quite standards-compliant and are rendered well in both Firefox and IE, are broken in Opera. But i didn't check it that deeply.
There's another problem: If it would have perfect support for web standards and show some sites wrongly, i would still respect it; but its interface is not that good either. The only good things i found there are the ones which i find in Firefox too - tab-browsing in general and middle-click opening a link in a new tab; indeed these are my favourite features in Firefox (and everyone else's too). But except that there's nothing particularly good. Ctrl-T, instead of opening a new tab, shows the
Add a bookmark dialog. When i wanted to open a new tab in Firefox for the first time, i figured out that Ctrl-T opens a new tab by myself - it was intuitive. God only knows how Ctrl-T is related to bookmarks. In the default skin it's hard to tell which tab is the current one, their colors are almost the same. All the fade effects add nothing; i'm not against them in principle, but here they are just superfluous.
Furthermore, it may have the fastest HTML rendering, but it feels non-responsive. When i type in a URL and press enter, i expect something to happen - in Firefox there are the dots moving in a circle, in IE there's the waving Windows logo, but in Opera there's nothing - it just looks as if it's stuck. No good.