That’s a surprise.
I expected Opera Mini to be approved because I thought it used the system’s WebKit component to display pages after they went through Opera’s servers; but it’s very obvious when you use the app that it renders the data itself. Possibly faster than WebKit, but clearly uglier. Makes it odd therefore that Apple would set a precedent of allowing a third-party browser engine on the iPhone; will they be able — or want — to reject Firefox after that?
Anyway, here’s what it comes down to: the interface is nice enough, but the multitouch is pretty awful (scrolling and pinch-zooming are both unpleasant, because Opera doesn’t use the system algorithms that make the iPhone so… right), my website looks ugly as sin in the browser, and all your data goes through Opera’s servers. In exchange, you get a possible speed increase on very slow connections.
The only people who’ll think it’s worth the tradeoff are the people who choose to buy Android phones.