The new iPhone 5 is coming out on at least eight carriers in the U.S., including three of the big four: AT&T, Sprint, and Verizon Wireless. Which carrier should you choose? Here at PCMag, each year, we run two extensive features assessing wireless carriers: our 30-city Fastest Mobile Networks test, which measures data speeds, and our Readers' Choice survey, which gauges coverage, call quality, and customer satisfaction.

I'll profile all of the announced iPhone 5 carrier below. But here's a simple rundown.

If you don't want to think, get Verizon. Verizon has the best nationwide 4G network and scores tops with our readers.

If you're in a 3G-only area, or use your iPhone as a car GPS, get AT&T. AT&T's 3G network is faster than Verizon's in areas where 4G isn't available. AT&T also allows you to talk and use the Web at the same time, which is important for in-car applications.

Other carriers offer price or usage bonuses at the expense of speed and coverage. Sprint's unlimited data, T-Mobile's (yes, T-Mobile's, more on that in a second) and Cricket's lower monthly rates, and the regional carriers' great local customer service are the killer features for each of those. But they all require a little more thought because of limited high-speed coverage.

If you have a great Verizon or AT&T plan that the carrier no longer offers (some special discount, promotion, or unlimited data, for example) you'll probably stick with your existing carrier. Nothing I say below is going to change the magic deal you got five years ago. If you're in the market for a new carrier or plan, though, read on.

Verizon Wireless: If Your City Has Verizon LTE

In my mind, 4G LTE is the most important feature in the new iPhone. It's much, much faster than 3G. Verizon came out tops in both of our surveys this year because of coverage and network quality. 

In our Readers' Choice awards, Verizon beat the other iPhone carriers on coverage, dropped calls, data network speed and reliability, and was the carrier our readers were most likely to recommend to others. Comparative Readers' Choice carrier scores are shown at right; U.S. Cellular does not carry any iPhones.

Verizon won our Fastest Mobile Networks national award by offering massively more 4G LTE coverage than anyone else; right now, it's up to 371 markets compared to AT&T's 60 and Sprint's 15. Verizon is also managing its network well, which leads me to believe it will be able to maintain speeds under the iPhone 5 crunch.

Verizon has a broad range of plans whose prices get very complicated, but one of the more popular plans for iPhones will likely be the $120/month option, with 6GB of data and unlimited talk and text. If you don't need that much data, 4, 2, and 1GB plans are also available at lower prices. 

AT&T: If You Want To Talk and Surf, Or Don't Have Verizon LTE

AT&T has two big advantages, and two big disadvantages, when compared with Verizon.

Advantage #1: Talking and surfing. When you take a call, your Internet connection doesn't pause. This is important if you spend a lot of time in the car and use your iPhone as a GPS.

Advantage #2: Faster 3G than Verizon. AT&T's 3G is on average twice as fast as Verizon's, according to our tests. So where Verizon's 4G isn't available, AT&T beats Verizon on speed.

Disadvantage #1: Reliability problems in major cities. In our Fastest Mobile Networks tests, we found AT&T's 3G network dropped connections more than 10 percent more often than Verizon's in New York, Washington, Los Angeles, and eight other major cities. Even if you're doing most of your surfing on AT&T's much stronger LTE network, an unreliable 3G network may mean dropped calls. (For more, see this earlier story.) In our Readers' Choice survey, our readers rated AT&T the worst national network for dropped calls and data network reliability.

Disadvantage #2: Less 4G LTE coverage than Verizon. With just 60 markets compared to Verizon's 371, AT&T has a long way to go to match Verizon's 4G strength nationwide.

AT&T's plans are generally comparable to Verizon's on price, give or take a few dollars. Its 6GB data plan with unlimited talk and text starts at $125 per month.

Sprint: For Heavy, Patient Data Users

Sprint's network is really struggling. In our Fastest Mobile Networks test we found it to be the slowest national carrier, with 3G speeds averaging 410kbps down. That's half of Verizon's speed, and one fifth of AT&T's. Nationwide, reliability was also far below Verizon's, with about 19% of connections failing, compared to Verizon's 3.3 percent of failed 3G connections.

Sprint has just begun turning on LTE, but coverage is very limited and the company has only half of Verizon's LTE spectrum per city, so it'll have to manage the network carefully to maintain a solid experience.