Actually, speaking as a normal user, i dont really notice those differences. The web pages i visit look the same to me on Chrome, Firefox and Opera ( but maybe thats just me, an average user). I guess from a developers point of view opera might lack in a few departments but for me its the only 'complete' browser.

The only thing i hate about opera is the lack of extensions. Despite the fact that Opera enabled extension support more than a year ago, they only have 918 extensions in their library ( which is a joke if you ask me).