Not trolling, I'm trying to figure out what practical benefit Opera has for its users.
For me personally, for fairly normal browsing requirements on a 2004-vintage Windows PC:
IE7/8: far too slow. Takes about 5 seconds just to open a new blank tab.
Firefox: faster than IE, but still really struggles with lots of tabs are open. Especially annoying that if one tab is slow to load, it slows down everything.
Chrome: Much better performance than either of the above. However, seems to crash rather a lot, and seems to have a bug that means it intermittently does not respond to Windows' "Tile Windows Horizontally" / "Tile Windows Vertically" commands (right-click on the taskbar.) As I use this feature rather a lot, it is really annoying to have to reposition
Opera: Similar performance to Chrome, but doesn't crash and doesn't have the windowing bug.
So I use Opera as my normal browser, with IE or Firefox waiting in the wings if I find a site doesn't work nicely with it.