We also measured ping times; Verizon, at 190 ms, was faster than AT&T's 301 ms.

The real-world download measure is the most important metric. Granted, throughput can vary greatly and is affected by a lot of variables. But this snapshot in time and location showed AT&T with a roughly 2.5-times advantage, a significant difference.

Now that the Verizon iPhone 4 is generally available -- along with Verizon's voice, text and data plans -- it's easy to will look like. For 400 minutes of voice calls, unlimited texting and unlimited data (or 2GB data for newer AT&T customers), plus an estimated $10 for fees, figure around $100 per month with either carrier.

AT&T makes it easier to reduce service levels to save money, but its bill is also more confusing, and there's little you can change yourself on their Web site.