Apple iPhone 12 Review: Superfast Speed, if You Can Find It

That led me to conclude that Verizon’s coverage map was unreliable.

Still, I drove to three other locations in the city’s Marina, Presidio Heights and South of Market districts. There, I finally found the fabled superfast 5G — and I was blown away.

Standing in front of a camera store in South of Market, I got 5G speeds reaching 2,160 megabits a second, which was 2,900 percent faster than 4G. Even where it was a tad slower — behind the Safeway parking lot in the Marina district — the 5G iPhone drew speeds of 668 megabits a second, which was 1,052 percent faster than 4G.

These were odd places to have blazing fast speeds, though. Even before the coronavirus pandemic, these areas did not have much foot traffic. The carriers have said ultrafast 5G speeds would be great for data-heavy tasks like streaming video, but I had no desire to do much streaming while standing on those street corners.

Why the nondescript locations? Karen Schulz, a Verizon spokeswoman, said the company ran into complex engineering tasks in San Francisco. While ultrafast 5G relies on access to light poles, most of the city’s utilities infrastructure is underground. Verizon’s progress to deploy 5G has run into red tape, she said.

When I tested the new iPhones on the vanilla 5G network, any speed improvement was hardly noticeable. In the best cases, vanilla 5G was twice as fast as 4G, or 209 megabits a second compared with 103 megabits on 4G. But in some locations, 5G was slower than 4G. In one part of the Mission district, for instance, 5G speeds reached 28 megabits a second compared with 39 megabits on 4G.

Ms. Schulz said that customers should initially expect the 5G Nationwide network to perform like 4G, and that performance and coverage would grow over time.

I’m not sure that’s good enough. I’ve reviewed phones over the past 12 years and covered the transition from 2G to 3G, and from 3G to 4G. I have never seen a network rollout this confusing and spotty — 5G, simply, is a mess.