I'm a long time Opera Mini user, and I've been playing with the new Mini 6 on my 9550 Storm (VZW, OS 5) for a week or so now. Overall, it's faster and smoother than Mini 5. They've also fixed the annoying bug that left half the screen missing after editing text (and subsequently hiding the keyboard). That alone makes it a useful upgrade.
They've added a jump to the top or bottom of a page. When you fast scroll, a button pops up on the screen; tap it and it jumps to the end in the direction you were scrolling.
In testing, I was able to download a 10 MB, a 20 MB and an 80 MB file when connected via wifi, and it held through a phone call in the middle. In a test download over VZW without wifi enabled and with a short phone call interrupting, it was able to resume the download after the call.
The only annoyance I've found so far is that I can't edit a URL in the address bar. I can backspace over it. I can copy it out, edit it, and paste it back in. But I can't edit it within the address bar.
Mini 6 won't play flash, and doesn't support animated gifs (but it will open them in the native browser).
As with prior versions, Opera Mini converts web pages on their servers, then sends an optimized page to your phone. I find it much faster than the native browser with ordinary pages, especially large ones, and it dramatically reduces data usage if you get metered. It can present something similar to what my Blackberry calls the "page view" and the "column view", and jump back and forth between them quickly.
All in all, I'm quite satisfied with Opera Mini 6. To download it, make sure your native browser is set to blackberry mode (not firefox or IE), and go to http://m.opera.com
. Go to the Opera Mini Forum
for more info.