Opera Mini™ is a fast and tiny Web browser, that allows you to access the full Internet on your phone. ... The new version further improves the browsing experience by enabling download of images, MP3s, etc directly to your phone.
I've had previous version of OperaMini running on my Nokia 6230 phone and pretty much always preferred it to the stock Nokia browser. The only drawback was when accessing operator-enabled resources that did not like Opera, but in every other instance it was far superior to the default web browser.
First experience after upgrading — it definitely feels much faster. Opera states that:
Opera Mini uses a remote server to pre-process Web pages before sending them to your phone. Web content is optimized for your device, ensuring fast browsing and a great user experience. ... Opera Mini recognizes your phone and optimizes Web pages accordingly to provide faster browsing. link
This is quite impressive, and what is more important — it works. Web sites, though cramped into a tiny screen, “degraded” very gracefully in most of my tests — they were pretty much unrolled, following the structure and preserving styles as much as it was possible (i.e. if CSS called for leaving a 150px margin, that was not honored, while colors, pictures, fonts, etc. certainly was).