Opera is faster than Chrome for Flash intensive websites, however as good as Opera is there is some dumb design elements. Right clicking on anything text based which is highlighted allows an instant Google search IN A NEW TAB. For whatever reason Opera chose to open it in the same damned tab. Also you can highlight any text on a page and drag it to a search box in Chrome, back to Win 95 select,copy,paste,click search style thing.
Opera on the other hand has auto page refresh and is lighter in memory usage overall.
However the ideal browser will have the best of Opera and Chrome. The rest are also rans in my opinion. I doubt very much that IE9 is even close to the efficient and fast engine of Chrome. It's like when those prize fools claimed "Windows 7 is as efficient as XP" yeah whatever mate, try playing a DVD full screen with 24fps on a Pentium II 366mhz (even if you have 2gb of RAM)
Microsoft=Microcock.