Opera's main drawback is that it doesn't have add-ins as Firefox does, so you won't be able to extend the browser's features. You can download Opera widgets, but they aren't really add-ins -- they're instead gadgets that live on your desktop.
Apart from the lack of add-ins, though, you'll find Opera an excellent browser. If you're looking for a great blend of simplicity and features, it's well worth the download.
-- Preston Gralla
Shiira is a relatively new entrant to the Mac Web browser market. Like Apple's Safari and Google's Chrome, Shiira is based on WebKit.
One of the first unique interface elements that I noticed was Shiira's PageDock. The PageDock provides the same functionality as tabbed browsing, but with complete thumbnails of every page that is opened.
At first, I saw this as something that took up valuable screen real estate, but after a little use, I found it to be an invaluable addition to the browser experience -- making it easy to see not only what each "tab" was (beyond just a name), but also what was happening on each page, which proved particularly nice with any page that sported dynamic content (from Facebook chats to sites featuring animation elements). For those who prefer traditional tabbed browsing, the PageDock can be turned off.
As I explored Shiira, I noticed that many of its features and interfaces took cues from Apple's Mac OS X interface. There's a button that displays all open pages next to each other like Apple's Expos? feature, making it easy to pick one page to work with. Bookmarks, history and RSS feeds can also be browsed from floating translucent pallets reminiscent of Apple's iLife and iWork applications.
The preferences dialog borrows heavily from the look of the Mac's System Preferences application. Even the bookmarking tool that Shiira refers to as the Shelf offers column and list views patterned after the Mac's Finder window (as is the customizable window toolbar).
All of these made Shiira seem more Mac-like to me than Apple's own Safari browser. What I found particularly nice was that, much like the PageDock, these features all served useful functions rather than just being eye candy.
I also found a couple of unusual features that seemed so intuitive that I couldn't believe they weren't more common in other browsers. These include menu items for automatically e-mailing the URL or entire contents of a page with a single click, and a very effective full-screen-mode option that would be perfect for presentations or watching video.
As far as performance, I found Shiira to be very solid. It loaded pages of all kinds, rendered Flash animation with no problems, and even beat out Safari and Firefox in terms of rendering speed on a couple of pages (albeit not by a particularly noteworthy margin). The browser was also very stable. All of this is important because, bells and whistles aside, the most important piece of a browser to me is that it can actually surf the Web painlessly and quickly.
Unfortunately, I did see some unfinished aspects of this open-source browser. Some of Shiira's preference options seemed unfinished. For example, the RSS feed preferences pane refused to open at all (even so, the built-in RSS reader functioned fairly well -- though being used to full featured stand-alone RSS readers, I'm not sure it would be my first choice). In addition, the pane in the preferences dialog called Key Mappings, which should allow users to assign keyboard shortcuts to menu items, does not seem to be implemented yet (though I was able to open the pane itself).
Even so, the combination of good features, Apple-inspired interface and overall performance left me convinced that, with a little more development, Shiira could easily give other Mac browsers a run for their money. Without a doubt, Shiira is definitely worth a look, but be prepared to spend a little time getting used to its interface.
-- Ryan Faas