With the iPhone 12 likely to arrive next month, prospective shoppers may be considering whether to move to a new wireless carrier when they get their new phone. With all four of Apple's newest smartphones expected to offer 5G connectivity, and the 5G experience currently offered by the three national carriers being very different, the question becomes especially relevant for the iPhone 12.

The timing is therefore particularly interesting for RootMetrics' latest report on wireless carrier performance, released this week. The report examines network speeds and reliability during the first six months of 2020 and includes important data on 5G performance.

The results show that AT&T has the fastest network overall, but Verizon won or shared six of the seven awards given by RootMetrics in this report, winning overall performance, network reliability, data performance, call performance, and once again took top honors with a complete victory in performance. Verizon also had the fastest 5G speeds, which is not surprising given its focus so far on high-speed millimeter wave-based 5G, but its 5G reach is not as good as AT&T or T-Mobile.

Focusing on 5G for a moment, RootMetrics described Verizon's 5G speeds as "outstanding." In contrast, RootMetrics said T-Mobile's 5G speeds were "similar to 4G LTE." But that only tells half the story; RootMetrics' testing period coincided with the completion of T-Mobile's merger with Sprint, and the Uncarrier was in the process of incorporating Sprint's midband 5G spectrum into its network. Therefore, T-Mobile's 5G performance is expected to improve, but this is not reflected in this report.

In addition, T-Mobile enjoys the widest 5G reach of the major carriers, with 5G connectivity in 112 of the metro areas tested by RootMetrics; AT&T was second with 78 metro areas; RootMetrics only had 27 Verizon cities with 5G results were recorded.

These numbers reflect the different strategies used by each carrier to deploy 5G networks, as seen in similar studies by other testing companies such as OpenSignal. Verizon initially used mmWave-based 5G, which offers significant speed gains but has limited reach and is best deployed in dense urban areas; T-Mobile and AT&T used low-band spectrum to build nationwide 5G networks because However, the speeds are not as high as those of LTE. However, transmission speeds are only slightly faster than LTE. That's why T-Mobile is eager to add Sprint's mid-band spectrum to improve 5G performance.

So what does all this mean if you are considering 5G coverage when purchasing the iPhone 12? Verizon certainly offers the best 5G speeds at the moment, but that is limited to some areas in about 30 major cities. Later this year, however, Verizon plans to use a technology called Dynamic Spectrum Sharing, which should improve network reach; AT&T and T-Mobile's 5G signals will still reach more areas than Verizon's when the iPhone 12 likely, and these two carriers are looking to improve their own performance.

So it may be helpful to take overall performance into account as well, and at least according to RootMetrics' calculations, Verizon stands out here. in addition to topping RootMetrics' overall ranking, Verizon has the highest reliability, call performance, data performance, and accessibility were the best. It shared the top spot with AT&T and Sprint in text performance.

AT&T won the speed category, with a median download speed of 42 Mbps for the entire US. Verizon was second with 36 Mbps and T-Mobile was third with 20 Mbps.

While the RootMetrics report noted that T-Mobile offers high speeds in urban areas, the results were not very encouraging for T-Mobile, as it came in last in six of the seven categories measured by the testing company The results are not encouraging for T-Mobile. Root Metrics states that "In many ways, the first half of 2020 is a transitional period, and work is underway that will allow T-Mobile customers to make significant leaps in performance going forward."

This report is based on 2.7 million tests conducted at more than 3,000 locations in 125 metropolitan areas in the United States.