Downloaded/Installed the Bèta 2 version of the new Opera, version 9.5 (last real version; 9.25 if I am correct). Gets me a quite nice
Acid3 score of 78/100, but not that that says much because most sites are still IE calibrated... And seeing IE gets a score of 12 in Acid3 I'd be willing to discard that score anyways.
Nonetheless, it has a built in IRC-client which I use all the time (and is very easy to use as well). Also how everything is standard ergonomically placed (such as the url-bar). But ofcourse if you dislike the placing of it all you can change it, you could even put the url-bar at the bottom of the page if you want.
Also the mouse gestures (somewhat the key signature of Opera) are great seeing I open up tabs a lot, the speed dial is great as well.
Without tweaking either FF or Opera, Opera is faster, with Tweaking FF an Opera, Opera will still be a tad faster (although the difference is not much).