Artificial IntelligenceCryptocurrencyMetaverseCybersecurityTech Forward

5G is supposed to be the future. But here’s what it’s like today

January 24, 2020, 12:30 PM UTC

I sat down on a bench in Providence, R.I. recently and pulled out a Samsung smartphone on a sunny winter day to test what’s billed as the future of wireless: 5G, the super-fast successor to today’s mobile networks.

After opening Netflix’s app, I started downloading an episode of the rebooted Lost in Space series, the one with Will Robinson searching for his missing robot pal. After just a few seconds, I saw the “checkbox” icon signifying the download was complete. At that rate, I could have downloaded the whole 10-episode series in 30 seconds—a phenomenal accomplishment that shows how 5G could fundamentally change what people can do with their phones.

But half an hour later, sitting a few blocks away on a stone bench on Brown University’s campus, that same phone, a Samsung, Galaxy S10 5G, couldn’t reach the 5G network, so it connected using slower 4G LTE. This time, downloading one episode of Lost in Space took more than 11 minutes, an eternity compared to the hype and maybe even a little slower than the average 4G connection.

And so it goes for wireless consumers in the early days of 5G—inconsistent and uneven. In some places it’s a magical wonderland of instantaneous satisfaction while, in others, even where 5G is supposed to be available, it’s nowhere to be found.

I experienced both sides of 5G during six weeks of testing around Boston, in Rhode Island, and in Las Vegas through T-Mobile, AT&T, and Verizon. The bottom line is that 5G is ready for early adopters who get a thrill out of having the latest mobile technology, but the rest of us should wait six months to a year for carriers to improve coverage and reliability.

Mobile carriers have already spent billions of dollars over the last few years to get to this point. But they’ll have to spend tens of billions more, and add hundreds of thousands of new cell sites, before 5G coverage is as accessible as current 4G networks.

It’s not just an infrastructure challenge. Current 5G phones from Samsung, OnePlus, and others are limited by today’s 5G chips that can’t access the faster networking technology that the carriers want to use. More capable chips are coming in phones later this year (including, if the reports are accurate, in new iPhones).

Currently, spending $1,000 or more on a 5G phone—compatible phones are required to use 5G—will only occasionally provide faster downloads. There aren’t yet any killer mobile apps that take advantage of wireless 5G, like realistic virtual reality games or multi-angle live sports broadcasts. As with the most innovative apps that grew out of the 4G era, like Uber and Airbnb, amazing 5G apps could take a few years to emerge and may not even be on our radar yet.

How fast is 5G?

That eureka moment of mine with 5G in Providence came while using Verizon’s network. On prior multiple tests in Boston and Providence, it had usually taken me at least 30 seconds to download a Netflix show on Verizon 5G compared with five to 10 minutes using a 4G connection.

But the day of the three second download, using Ookla’s Speedtest app, I saw the network’s download speed was hitting 1.3 gigabits per second, or more than 40 times faster than the average 4G connection. To put that in perspective, it was also faster than most home Internet connections.

Still, even in Providence on a single day, 5G speeds vary. After my super-fast download and then super-slow download on Brown’s campus, I headed inside a nearby coffee shop and found a 5G signal. There, downloading a Lost in Space episode took just one minute and 28 seconds. In Boston on another day, similar downloads took two to four minutes —even on Verizon’s 5G network. And in Las Vegas, it took about five minutes with no 5G (Sin City isn’t among Verizon’s first 31 to get the faster technology).

Verizon’s limited rollout, at its best, was considerably faster than AT&T and T-Mobile’s in my tests. Those two carriers have chosen to roll out 5G using typical cell phone airwave bands that don’t allow for the highest speeds, but provide far greater coverage areas. Verizon’s strategy of using higher frequency airwave bands provides 5G over a smaller area, but with much higher speeds.

5G indoors versus outdoors

The type of 5G deployed by Verizon doesn’t penetrate walls and windows as well as typical 4G cellular signals, or the 5G used by its rivals. During tests of Verizon in Boston, I got an average download speed of 132 megabits per second inside a doctor’s office and, in a coffee shop in Providence, 153 megabits.

But outdoors in Boston and Providence, download speeds were several times faster, with average speeds of over 600 megabits and reaching as high as 1.4 gigabits.

The gap between indoors and outdoors for AT&T and T-Mobile wasn’t as dramatic, but then neither were their top speeds. In Las Vegas, I had 5G download speeds for both carriers of almost 150 megabits per second outside, or about four times faster than an average 4G connection. Meanwhile, in my hotel room, speeds were 80 to 90 megabits. In my local Boston suburb, T-Mobile was an average of 130 megabits per second outside compared with 107 megabits at a local cafe.

To be sure, I used a different phone to test each network, which likely impacted the results. Download speeds can also be impacted by Internet congestion, cell tower equipment, and other factors.

How good are 5G phones?

Currently, there are only a few 5G compatible phones available—and they’re all pricy. Verizon sells two Samsung models along with one from LG, all for $1,000 to $1,300. AT&T has only the Galaxy Note10+ 5G, for $1,400. Meanwhile, T-Mobile sells the Note10+ 5G for $1,300 and OnePlus’s 7T Pro 5G for $900.

The phones are just as capable as their non-5G brethren. I got at least a full day of battery life out of all of the 5G phones, and they didn’t heat up or experience glitches, even as I performed multiple downloads and dozens of speed tests daily.

three 5g phones
Current 5G phones include the Samsung Galaxy Note 10+ 5G, Galaxy S10 5G, and the OnePlus 7 Pro 5G.
Aaron Pressman—Fortune

The phones have crisp, bright displays that are good for watching downloaded or streamed videos, matching the quality of 4G phones. But they are also all relatively bulky. Including components for connecting to 5G networks and 4G as a fallback means the devices are similar in size to the largest 4G phones. None of the 5G phones currently available has a screen smaller than 6.3-inches.

Future 5G phones should be cheaper. For example, TCL, best known for its low-priced TV sets, recently showed off its upcoming TCL 10 5G model, priced at $500. But the device is at least as big as Samsung’s 5G giants, and it’s unlikely that phonemakers will be able to make smaller phones this year.

5G improvements are planned

For now, mobile carriers offer 5G in limited areas. Verizon’s service is available in only parts of 31 cities while AT&T covers 20 cities for consumers. In contrast, T-Mobile’s slower 5G covers a territory in which 200 million people live, or two-thirds of the nation’s population.

Over the next few years, all three carriers have said they would expand their networks and improve download speeds. More specifically, AT&T and Verizon hope to provide near-nationwide coverage later this year. Meanwhile, T-Mobile says it will make its network faster, but that’s dependent on the company completing a proposed merger with rival Sprint that would provide it with more airwave licenses (the merger is still being reviewed by a federal court).

One result of the slow roll out by the carriers is that current 5G phones—even the most expensive—will be unable to take advantage of everything that expanded networks will offer later this year. That’s mainly because carriers will start using 5G airwave bands that current phones can’t handle. It will take brand new 5G models to handle all of the bands in use. But that’s been the natural evolution of the wireless market for decades–the fastest speeds are only available to the newest devices.

Considering my mixed experiences with even the most expensive 5G phones, that’s an evolution can’t come soon enough.

More must-read stories from Fortune:

A.I. in China: TikTok is just the beginning
—Inside big tech’s quest for human-level A.I.
—Medicine by machine: Is A.I. the cure for the world’s ailing drug industry?
—A.I. breakthroughs in natural-language processing are big for business
A.I. is transforming the job interview—and everything after

Catch up with Data Sheet, Fortune’s daily digest on the business of tech.