T-Mobile competes very well against the larger carriers—namely AT&T and Verizon—on price, features, and CEOs in leather jackets. Where it's somewhat less competitive is reliable service. To help bolster its performance cred, the company now offers a "4G LTE CellSpot" to help shore up reception at home or at work.

This isn't the first home improvement project for T-Mobile; it had previously offered a Wi-Fi CellSpot router to achieve similar ends. Since T-Mobile also offers Wi-Fi calling on all of it phones, that theoretically should have done the trick. But Wi-Fi calling can be spotty under the best of circumstances, and 4G LTE reinforcement should suffer fewer hiccups.

It's also not the first time a company has offered a "mini-tower" to make up for uninspired connectivity. AT&T started selling its 3G “MicroCell” in 2010. The key word there, though, is "selling." While there have been reports that AT&T customers could complain their way out of a MicroCell fee, it cost $150 at launch. It also only boosts 3G connections, which was fine at the time but is downright pokey by today's standards.

By contrast, T-Mobile's CellSpot is effectively free, provided you pay a refundable $25 deposit and remember to return it at some point. In return, you get what is effectively a tiny, localized cell tower that can cover up to 3,000 square feet in glorious 4G LTE, and up to 16 calls at one time. It also requires very little set-up; just connect it to the internet and plug it into an outlet and enjoy the power-up.

There's no real apparent downside to T-Mobile customers, other than the reminder that a signal-boosting device is unfortunately still necessary for many of them. In a recent report ranking wireless carriers on reliability, speed, data and call performance, and text performance from analytics firm RootMetrics, T-Mobile finished last overall, and fared especially poorly in call performance and network reliability.

RootMetrics

T-Mobile may bill itself as "America's fastest LTE network"—a claim which the RootMetrics study also disputes—but those speeds don't mean much if you can't access them.

In fact, your best hope as a T-Mobile customer is that the 4G LTE CellSpot lands in as many households and offices as there are subscribers. T-Mobile has invested heavily in its infrastructure, but it still has a significant amount of catching up to do. This way, at least, it will get a bit more reliable—3,000 square feet at a time.