Opensignal is an analytics company that uses aggregated data from smartphones to generate reports on carrier performance. For the July edition of its US metrics, in both its overall mobile experience and 5G-specific reports, T-Mobile edged out its competition in the "big three" US carriers. It seems the acquisition of Sprint has truly leveled the playing field, as no carrier between AT&T, Verizon, and T-Mobile was able to make a clean sweep of either report.
For mobile performance, T-Mobile took the US crown for voice app experience, upload speed experience, and both 4G and 5G availability. It also bested all comers for 5G reach as well as 5G upload and download speeds. Verizon took prizes for general video experience and 4G coverage experience, as well as 5G games experience, 5G voice app experience, and a combination 5G video experience with AT&T. That's the only metric in which AT&T placed on the 5G chart, though it bested the competition in the overall games and download categories.
Most of those metrics don't mean a lot for users in specific markets; just because Verizon has the best nationwide video performance doesn't mean it'll perform best in your town or city. And in most of the tests, the difference between the best and worst performers was marginal: Opensignal scored T-Mobile, Verizon, and AT&T 78.8, 78.0, and 77.9 out of 100 for Voce App Experience, respectively. You'll want to dive into the individual market results to get information that's actually relevant down to the metro area.
It's the 5G race where T-Mobile pulled ahead dramatically. According to the aggregate results, T-Mobile's 5G download speed was 35% better than AT&T and T-Mobile on average, with upload speeds that edged out Verizon and handily beat AT&T. T-Mobile's 5G availability and reach were similarly ahead of the competition, while the metrics for video experience, games experience, and voice app experience were much closer contests.