One of the reasons I didn't use Opera was actually because Web developers never tended to create content with Opera's rendering engine in mind. This lead to a few weird quirks on some badly(lazy?) coded web pages, sometimes breaking the whole thing altogether.
Now, I'm going to give Opera another go. I really like browsers features, however now I don't need to compromise my web
experience on the rendering level in order to use it. Good move in my opinion, as I don't think the web really benefits from multipul rendering engines /unless/ one of them goes stale and prevents innovation (Anyone remember Internet Explorer 6?). So long as the rendering engine to webkit or Mozilla's web engine allows the web to grow, I am happy with only one or two out there.