T-Mobile's 5G coverage is live, compare with Verizon, AT&T and Sprint 4G speeds by band

On the eve of flipping the 5G switch over at 's "nationwide" network, the crowdsourcing testers from OpenSignal came out with a breakdown of what the good ol' 4G can achieve in terms of download speeds... by carrier band.

A lot, it turns out. While 5G can reach amazing speeds, they are reserved only for the mmWave bands like Verizon's or AT&T's that have low building penetration and require you to, ahem, hold the phone right.

The mids of Sprint and lows of T-Mobile cast a wider net, but are slower, ...