Of all the browsers I’ve worked with SafariDriver is too fast. Fast is good but too fast has some issues too.
Don’t know about Opera, but Chrome and/or Firefox is next in fast speed. I don’t test Chrome enough to say if faster than FF but think so, with IE being slowest.
With all the other browsers, FF/Chrome/IE, you can see the visual activity happen in most cases. But SafariDriver does it so fast, you don’t get to visually monitor & verify that what’s automated actually working well other than whether test passes or you get some exception from SafariDriver.
I’d prefer to be able to see the automated actions during a test run…