The Opera Mini is still the fastest browser out there, whether it be Symbian (my old E71) or Android (my current X10 Mini Pro).
But it's still missing some key features. The most recent update (version 5.1) has strangely removed keyboard shortcuts for page down and page up. The iteration in Opera Mini 4.2 worked the best, with the left and right arrow button serving as the page up and page down keys.
Version 5 changed the mapping to the numbers 2 and 8 respectively. On a QWERTY keypad, this meant having to toggle the persistent numeric key-entry mode first (normally 2 presses of the Function key), and then the number. Still, it was tolerable.
The page formatting isn't exactly fantastic too, but the speed (and speed is the most important factor for browsing) is blazing...