I've been a big Firefox fan for years, and still use it as my primary browser at work and for all my web development, thanks to the great Firebug plugin, but recently it's performance has started to really both me, both at home on the Mac and at work on Solaris.
I'm quite limited in what I can use at work as we run everything on Solaris/Nevada, but I've got full control over my home browsing experience. So today I downloaded Opera 9.5 Alpha for the Mac and took it for a spin.
I've dabbled with Opera on and off for years, but never quite settled. I'm not sure if I'll settle on it now, but I have to admit I'm very impressed. It's amazingly quick, and surprisingly stable considering its only an alpha release. The only stability issue I've found is it can hang when changing some of the advanced preferences and then saving them. The only cure for this is to restart Opera.
Other than that, I've only got three niggles at the moment:
No matter what I do, I can't work out how to change this.
Update: As luck would have it, moments after making this post I discovered a way of putting the address bar above the tabs, but this method doesn't work for the bookmarks bar (Personal Bar in Opera). So I guess I've partly resolved this niggle.
Other than that, what an amazing browser. Now if only they compiled the Solaris version for use with GTK instead of QT, I'd seriously consider switching to Opera for use at work.
That said, it is encouraging to see Mozilla developers are switching to Solaris so they can use DTrace. Who knows, maybe we'll be seeing Opera performance from Firefox in the not to distant future.