Opera already offers, but it relies on a server to translate your requested pages into a stripped-down form. It's fast, but not the full experience. Opera Mobile is the real thing, a full Web browser that could give the good default Android browser a run for its money, while joining Mozilla and Firefox 4 in taking its desktop experience mobile.
Opera has made a big noise about hardware acceleration, a feature which should allow its Android browser to run quickly, making navigation faster and improving the user interface.
Opera Mobile for Android also allows pinch to zoom, which current versions of Opera Mobile and Opera Mini don't have. This allows you to create your own fluid level of zoom. This could make a significant difference, as the current two levels of zoom for full page width and text reading isn't quite good enough for high-end smart phone users. A forthcoming version of Mini will offer this too.
Opera has had a stranglehold on mobile phones in recent years, offering a browser which did a decent job on the majority of phones. But with high-end smart phones such as theoffering such brilliant default browsers, Mini is looking outdated. With Mobile for Android, there's also an opportunity for the Norwegian company to make up some ground and develop the browser further with Firefox-style extensions and Flash support, although these won't be present in the new version.
More options for Android users can only be a good thing. Firefox recently released the beta version of the Android browser it is developing, codenamed, so browser competition on Android will soon be very fierce.
On the desktop you have Internet Explorer, Firefox, Chrome, Safari and Opera fighting for your attention -- there could soon be a similar war for your Android mobile.