There was speculation recently that, in the face of Safari's integration into OS X, Opera Software would halt the development of Opera for the operating system. But, like Firefox, Opera 8 is advertised as a cross-platform solution, and so ignoring a large section of the userbase is unlikely.
Opera straddles the commercial and free sector but the company has recently announced the end of its advertsupported edition, which has been replaced by a completely free version. You will still be able to purchase support services for $29, however. This browser is also unique in this test group in that it integrates a whole suite of communication tools, including mail and news reading, within the main application.
Despite the loss of the advert bar, unobtrusive though it was, habitual Mac users and those raised on the clean simplicity of Firefox might balk at the nonstandard user interface Opera displays. It does keep everything to hand, though.
As with Safari and OmniWeb, the use of a non-standard web engine means that many sites "designed for Internet Explorer" will fail to load. And while the application does make it easy to change the User Agent String, it still exhibited problems with many of the banking sites we tested - mainly due to an issue with Cookies being rejected.
There are some nice touches to Opera - the top ten most visited list, mail, RSS and news integration, excellent theming - but many users may find it a minor pain to switch from the OS X way of working to the Opera way of working. The ads in the old free version weren't too intrusive, but they did add more visual clutter to an already very busy interface. Now they're gone there's one more reason to try Opera. If you desire an all-in-one solution, Opera is a good bet.