only 10% of the data is transported to your phone while Opera does the heavy lifting. If you are on a data plan that requires you to watch every MB of data that you use, Opera Mini is a big help. The use of hot keys allows 'Berry users to scroll up and down very quickly using Opera Mini. Lars Boilesen, Chief Executive Officer, Opera Software said, "As the world’s most popular browser, we want to take every opportunity for people to have access to our browsers, regardless of the device." For many BlackBerry users, the Opera Mini browser is a big upgrade from the stock browser on their device.
source: Opera via BerryReview