The problem starts with the obvious: The EDGE network can be impossibly slow. Its speed appears to vary from moment to moment, as a function of the current signal strength as well as more mysterious factors that you can neither predict nor control. Its speed range varies from barely tolerable to virtually useless. And the greatest negative impact of these slow speeds occurs when using Safari. There are times when it can take several minutes for a Web page to load; assuming it ever completely loads.
But the problems with Safari on the iPhone extend beyond just the overall slow speed. What often happens is that, after tapping to load a Web page, your hopes are initially raised. You see the progress bar advance (indicating that more and more of the page's elements have loaded) to as much as 80% completion in a relatively short time. Then it all just grinds to a halt. There is no more movement for an indefinite number of minutes.
Even this might be tolerable if, in fact, 80% of the Web page was now loaded and accessible. It might turn out that all you need from the page is within that 80%. However, more likely, your Safari screen will be blank. Absolutely nothing appears until after the bar moves past this 80% barrier. As a result, there are many times when I have given up entirely — until I can get to a Wi-Fi connection.
If you do wait long enough for the Web page to appear, your troubles may still not be over. Suppose there is a link on the page that you want to check out, but you also want to be able to return to the page you are now viewing. For example, suppose after you load the New York Times' home page, you want to click a link to read an editorial; but you also expect to return to the home page to scan the remaining article listings.
On your Mac, you would do this by opening up the editorial in a separate window or tab. Unfortunately, the iPhone's version of Safari does not support any variation of this capability. The best you can do is go to the editorial and then tap the Back arrow to return to the previous page. Ideally, this page should at least load faster than it did initially, because Safari had cached its contents. Don't count on it. Safari does do caching, but it is very ineffective in my experience. Typically, I have to wait almost as long for the page to reload as I did in the first place. Once again, I often wind up just giving up on Safari until I can get to a Wi-Fi connection.
What can be done to improve the situation? Four things, none of which should be a surprise by this point: (1) Improve Safari's caching of Web pages; (2) Improve Safari's ability to display partially loaded pages; (3) Add a tab (or similar) function to Safari; and most-of-all (4) offer a faster network than EDGE.
Happily, the faster network is all-but-certain to arrive with the new iPhones (apparently expected to ship any day now!). These new iPhones are widely reported to support the much-faster-than-EDGE 3G network. As to the Safari-specific upgrades, it's not as promising. The version of Safari included with the latest builds of the iPhone 2.0 SDK appears very much the same as the current version. Of course, Apple could be holding back a revamped version until the public release. I certainly hope so.