Opera is faster than Safari, Period. If you don't believe me, check out the tests here http://nontroppo.org/timer/kestrel_tests/
Opera is more customisable than Safari ever will be (and less buggy too, on Windows) and more than FF too out of the box
. Of course, it doesn't have Extensions (and it's widgets are a poor alternative), but then in FF, 7 out of the 9 extensions I use emulate Opera's features.
The day FF is as easy to personalise as Opera, and as fast, I'll switch. Check out my customised Opera screenie, http://www.osx-e.com/gallery/showimage.php?i=3668&c=507
PS: @gMac, that link you posted is woefully out of date. Opera hasn't been adware or payware since years now.