Indeed, I've tried opera a few times. Usually no performance or core web-browsing improvements I can see over the stock one I use (firefox/chrome/safari, depending on platform). But there's plenty of ugly and clunky that goes with it, that quickly loses my interest.
I find it practical, personally. I've always used WinXP with the Win98 'classic' theme, and Opera with the Opera6 theme. Not particularly beautiful but very responsive and easy to navigate.
