To Download, point your mobile browser: m.opera.com/next
I use the Blackberry Storm and Opera Mini 5 Beta for my device is amazing.
It's the most dynamic app I've had. I've used the BB browser, Bolt, and the previous version of Opera. Not much of a diverse range of browsers but enough to establish that Opera Mini 5 Beta is probably better than them all. It has smooth transition animations when switching to various functions, definitely a plus to the overall feel.
The crackberry forum talks about Rim updating the BB browser and it might eventually be better than Opera 5, but for now, this browser is great.
I've only been using it for 2 days and my opinion might change but I doubt it. For a Beta version it seems pretty solid.