Opera Mini has been approved for the iPhone / iTouch. Available for free in the App Store.
http://www.opera.com/press/releases/2010/04/13/
I have been playing with it on and off this morning and it is definitely a lot snappier than Safari and much more usable. So far I haven't run into any real issues with it. The first time I launched it the program locked up, but I hit the home button and re-launched it and it has run perfectly ever since.
One thing to be aware of when using Opera Mini is that they use some variety of data compression method. Basically their servers fetch the web page and all of it's content, compress it then send it to your phone. This makes the pages load way faster but it makes me kind of uneasy about doing like logging into my gmail using their browser. What do you guys think?