Opera 10 re-introduces a bug which had existed in prerelease versions of 9.5 but long since corrected. It does not integrate fully with the system in a way which makes it extremely frustrating to use as the default browser. It fails to properly launch and open URLs sent to it from other applications. It will launch, but open the home page set in prefs rather than the URL being requested by the application sending the message. If Opera is already running, everything is fine, but this bug is truly maddening. I am no longer willing to use Opera as my default, even though it is my preferred browser. This is a shameful regression that needs to be fixed!

The browser is fast, stable, and allows far and away the most flexible control over the browsing experience, but I can't tolerate this bug. Without it, I'd give it 5 stars, but not now. (Opera 10 is the only browser I have on my computer that does this. Opera 9.64 works correctly.)