The Opera Mini 4 beta helps the Treo 700p get closer to the "real" Internet as advertised by the iPhone. The beta has some bugs. For example, the keypad shortcuts don't work on the Treo, and it eventually runs out of memory (necessitating a restart). It's still a great alternative to the Treo's built-in browser.
Opera Mini vs. iPhone is totally uncalled for. The video touts that Opera Mini works on other phones besides the iPhone, which is supposed to matter because the iPhone is expensive. Who cares? The iPhone's browser kicks ass! It also uses Apple's open WebKit engine—the one Nokia chose for their spiffy Mini Map Browser.
If Opera really wants to get into a pissing contest: WebKit already supports 18 out of 19 documented CSS3 styles...
It's really unfortunate that Steve's WWDC browser market share slide implied that the world would only be left with two browsers: Safari, and IE. The folks at Opera and Mozilla should welcome the proliferation of another browser that supports open standards unless all they really care about is the search engine revenue derived from their own browsers.