First off, the Pearl and the iPhone I used both ran on the same network, which is to say AT&T's EDGE network. I can't say that either is super speedy for browsing. In fact, WAP sites on the Pearl often took as long to load as some full Web sites do in Safari. The little speed boost that AT&T gave its network on June 28th certainly improved browsing speeds for both devices. Here's the actual breakdown.
The browser is mediocre at best. It may be easy to launch from the BlackBerry home screen, but the controls are clunky if you ask me. The menus are not intuitive, and even with the QWERTY keyboard, pecking in URLs can be a pain in the neck, er, thumbs. I have found the best way to browse the mobile web it to create as many bookmarks as possible, which cuts down on the amount of actual typing you have to do. This is definitely effective for the Pearl, though accessing bookmarks takes a few steps.
Browsing speeds aside, though, most sites work well enough even if they don't look all that great. For sites that don't have WAP versions, the browser would attempt to recreate the entire page. With such a small screen, it led to a lot of scrolling around to see the content you wanted or needed. Navigating sites such as Craig's List were downright painful. The site that matters most to me, Google, loaded just fine and produced the results I needed it to, especially related to search.
But there are many sites that are simply not friendly to mobile devices. The bus company I use, for example, does not have a mobile site, and the regular site was completely unusable on the Pearl. This meant I couldn't check the bus schedule that I needed to find out when I could catch a ride home. I had to call the bus company instead, and they aren't that friendly to phone requests about bus schedules.
If you have a lot of forms-based Internet usage to do, it all depends on whether or not the forms are formatting for WAP browsers or full browsers. It can really be a mixed bag.
As a bare bones means of accessing the Web and certain information, the Pearl gets the job done adequately. There are definitely better browsers on mobile phones.
The iPhone is far and above superior at the Internet. I fully admit to eating some crow here, but the Internet experience is not that bad over the EDGE network. It compares to using the Pearl in terms of speed, but you get a much richer Internet. Bookmarks are simple to set up and use in the Safari browser. And you get the full version of Web pages. That makes a big difference.
Using the Safari browser, I was able to access and use my bus company's Web page and get the schedules I needed with out any problems. If you use the browser to sign into Gmail, you have access to some of the other Google services. I was able to get into Google Apps, for example, and see all my documents. I could open all of them, and perform searches with in the Apps environment, but once inside a document, you can't interact with it beyond reading what's in it. You can't enter text or compose new documents or make edits to documents. I was able to "share" documents with other users, though, which is helpful. I couldn't do any of that on the Pearl. Since I am a heavy user of Google services, ths works out really well and actually enhances my productivity quite a bit. But it would be better of I could edit the documents, even in a minor way. Other Google services, such as Blogger, didn't work.
For the one Web site I write for most, being able to see and access all of its features is a Godsend. On the Pearl, I could only reach the WAP version of the site. Now I can see all of it, and navigate and interact with the entire site from the iPhone. I can even pen posts from the iPhone. That also is a big productivity enhancer for me.
The large screen on the iPhone also goes a long way to making the experience a better one. Also being able to use the touch functionalities of the device itself to scroll around, and zoom in and out make navigating inside large Web sites far easier.
The iPhone outstrips the Pearl's browser big time. It's not even a fair comparison, really. The iPhone is so much richer and more fully realized, that it makes me never want to browse WAP sites again. Having access to the full version of the Internet (albeit, without Flash and other animations) in a device so small really is useful beyond words. The speeds aren't as fast as some I've seen on EV-DO equipped smartphones, but both devices are handicapped similarly here.
If your work requires access to the (mostly) full version of the Internet, the iPhone works better than the Pearl.
For me, the end result between email and Internet is a tie. The cons of the poor email capability are negated by the amazing Internet abilities.
Does that mean I am going to keep the iPhone? I dunno yet. I have until Friday to make up my mind...