Been using Opera since initial release on Windows (back in those days when it's still paid software). Somehow just couldn't shift to other browsers.
The latest 9.5 brought a few.. let's say.. unwelcomed changes to usability like new default shortcuts (shortcut profile can be switched to pre-9.5 releases) and no more instant google search on the address bar without typing the letter "g" in front of your search text (it used to be able to perform a google search on any text that has 2 or more words in the address bar without the "g" prefix).
Aside from the occasional weird webpage rendering, the latest version (9.5) loads much quicker than previous releases. On the whole, useable, but still needs fine-tuning.
Onto Firefox.. great alternative, but somehow finds it slow. Only use it for compatibility reasons. Other than that, it'll be Safari considering it launches almost instantaneously (on a new mac that is)..