The early reviews of Apple's iPhone are in and, while there is near-unanimous consensus that the handset is wonderful, most reviewers point to a major weakness: the slow AT&T network on which the iPhones will operate.

The Edge (Enhanced Data Rates for GSM Evolution) network can be painfully slow; it generally operates at between 75 and 135 Kbps. In a broadband world of users accustomed to the instant gratification of 600 Kbps to 3 Mbps, that slow speed will frustrate many iPhone subscribers.

The iPhone can switch seamlessly from Edge to a much faster Wi-Fi connection. But users will need to find a Wi-Fi hotspot, which, while widespread, is not as ubiquitous as cell phone networks.

"Speed rates [of Edge] will vary widely," said Joe Nordgaard, managing director of wireless consulting firm Spectral Advantage, in an interview. "The user experience will vary accordingly."

Nordgaard said users in congested areas later in the day when usage grows would find that their iPhone network connections will degrade. "It will help to be under a tower," said Nordgaard. "Particularly for Edge it will help to be near a tower."

"Wi-Fi will be the saving grace for the iPhone," he added.

Even influential reviewer Walter S. Mossberg of the Wall Street Journal, who tends to adore all things Apple, called Edge a "pokey network" in his review of the iPhone this week.

Early concerns about the iPhone's lack of a tactile QWERTY keyboard have disappeared. (Of the keyboard, Mossberg said: "It works.")

Nordgaard said AT&T engineers have worked to improve the Edge network in recent months, and the effort will undoubtedly help improve subscribers' experience with the handset.

In March, AT&T helped set the stage for wider Wi-Fi access when it announced that the company had deployed 34,000 hotspot locations.

To use many Wi-Fi hotspots, iPhone users will have to pay an additional fee, but many Wi-Fi connections are offered free of charge. Public libraries, for instance, usually offer free Wi-Fi connections.

AT&T does have a faster 3G wireless data network, but it isn't as widely deployed as its Edge network. So the iPhone can't access the 3G network. Apple chief executive Steve Jobs has said Wi-Fi should provide iPhone customers with all the speed they need to surf the Web on the snazzy new phone.