Opera, which has been around since 1995, has always been the underdog of the browser race, though it shares Chrome's clean appearance and speed. Because Opera efficiently uses caching when opening pages, it is especially well suited to slow connections. It uses less memory than other browsers, making it suitable for older computers as well.
The most recent reviews hail Opera's latest features, including a very workable voice command system. Reviewers also like Opera's stackable tabs and the preview thumbnails that appear when you mouse over a tab. Users can easily reconfigure the browser page to suit their preferences.
Opera's underdog status can be attributed in part to the fact that it has never come installed on a computer, like IE and Safari do. Nor does it have the big-name backing of Firefox and Chrome. That's not its major weakness, though. What reviewers most often complain about is the browser's lack of compatibility with some sites. For example, Opera does not support Netflix's popular Watch Instantly feature that allows viewers to play movies and TV shows without downloading them.
Opera will be attractive to anyone working with older machines and slow web connections; anyone else might become frustrated.