Hands on: When to choose Verizon's iPhone 4 over AT&T's

Thousands (or even millions) of people are strongly considering the purchase of the second coming of the iPhone 4 -- the one powered by Verizon. But what might have been a slam-dunk decision a year ago isn't quite so clear cut now.

For one thing, the next version of the iPhone is expected to be released this year (probably this summer). For another, AT&T's 3G network, while arguably less reliable than Verizon's -- especially in key markets, such as New York City and San Francisco -- is faster when you have a decent connection.

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And there are more issues. The Verizon iPhone doesn't support voice and data operations simultaneously. Plus, competition from Android-based smartphones is fierce, and they're evolving rapidly.

We've been testing the Verizon iPhone 4 at Computerworld. First, let's get this out of the way: Despite numerous reports about differences between the two versions of the iPhone 4, from a user perspective they're virtually identical. The Verizon version lacks a covered SIM-card slot, and the antenna has four dividers instead of three in the stainless steel rim. On the inside, there are several minor differences, the most significant being the new CDMA radio required for Verizon's network.

Connection strength
In our tests in the greater Boston area, the Verizon phone cleared up the one nagging issue troubling users of the AT&T iPhone: connection strength and reliability. Our testing showed that Verizon's network delivered significantly stronger reception than AT&T's. In one example, we found that the Verizon iPhone was able to grab three bars in Computerworld's gym, which is in the partially underground basement level of our office building. For the AT&T iPhone, this same room was a dead zone.

Try as we might, Computerworld editors were unable to reveal anything like the "death grip" vulnerability on the Verizon iPhone that we are easily able to demonstrate on the AT&T iPhone. Charles Starrett of iLounge published a convincing story with video demonstrating a reduction in reception strength apparently corresponding to grip position on the Verizon iPhone 4.

In addition to our own series of tests for this problem, we attempted to duplicate Starrett's results and came up empty. No matter what we did, the Verizon-based smartphone showed five bars and throughput was undiminished.