But Tello’s latency was significantly higher in general—not enough to affect a game of Royal Match, but maybe you have higher demands. The download speeds were also lower for Tello in any given location, but not by a whole lot.

At home, my cellular 5G data speeds tend to run at about 800 to 900 megabits a second on T-Mobile. With the Tello phone, it was around 30 percent slower. But both these speeds are well into 5G territory. They’re also a full order of magnitude faster than you’d ever need for 4K video. I had no problem streaming my usual dose of Josh Johnson comedy, if that’s what you’re wondering.

Curiously, upload speed was actually faster with the Motorola Razr using Tello than with the old iPhone using T-Mobile. After consulting with my colleague Julian Chokkattu, who has covered phone advances for years, I’m likely to chalk this up to improved modem performance by the newer Motorola, not a secret backdoor to faster uploads by Tello.

It’s only in areas with degraded or 4G reception that I started to see real lapses in Tello’s performance. In the outskirts of Portland near its forested northwestern ridge, Tello got fewer bars than T-Mobile—and the data arrived at speeds slow enough to bother me. A couple of speed tests timed out. Uploads also began to crawl in low reception areas as compared to my T-Mobile phones, sometimes dipping down into only a quarter of the speed of T-Mobile’s network.

Which is to say: Most of the time, Tello worked just as well as T-Mobile. Except for the stray moments when it didn’t. The moments when Tello’s performance is noticeably worse are usually the moments at which you’re demanding the most from your phone: clinging to a stray bar of reception, or streaming a video while riding a train.

When Would I Want Tello Instead of T-Mobile?

Whether the trade-off is worth it will depend on what type of phone user you are. Family discounts are better with the big providers. Frequent international travelers should also probably stick with the big boys. International roaming will cost you with Tello, as will texts to and from most countries outside Latin America and Europe. Travel is also when you’re most likely to use up lots of data outside Wi-Fi networks.

The other big financial differentiator is how often you upgrade your phone. With Tello, you’re on your own when it comes to procuring a device, while T-Mobile and other postpaid plans keep you hooked to their high-priced plans by offering you the latest and greatest gee-whiz phones at steep discounts.